#!/usr/bin/python
def factorial(n):
space = '*' * (4 * n)
print space, 'factorial', n
if n == 0:
print space, 'returning 1'
return 1
else:
recurse = factorial(n1)
result = n * recurse
print space, 'returning', result
return result
x=factorial(3)
print x

Draw a flow chart for this program
What if we change x=factorial(3) to x=factorial(5)
Change the flow chart
Monday, July 25, 2011
Python Data Types Code Example  පයිතන් දත්ත වර්ග
x = []
for i in range(0,10):
x.append(i)
print x
print "______________________________________"
y = x * 10
x = "Hello World!"
print x
print "______________________________________"
print y
# What are X and Y?
===================================
#############
# Arithmetic
#############
4 + 4 == 8
3  5 == 2
16 / 2 == 8
16 * 4 == 64
3 % 2 == 1 # Modulus
# Long Int Conversion  Useful for function type mismatches  Not needed here.
100000000000000000000L + long(100) == 100000000000000000100L
======================
##########
# Strings
##########
a = "Hello"
b = "World!"
# Concatenation
a + " " + b == "Hello World!"
# Repetition and Concatenation
a * 3 + " " + b == "HelloHelloHello World!"
(a + " ") * 3 + b == "Hello Hello Hello World!"
# Indexing
b[2] == "r"
# Conversion of data to string  Sesame Street:
c = 7 # Backquote ` ` or str() operations
( a + " number " + `c` ) and ( a + " number " + str(c) ) == "Hello number 7"
============================
for i in range(0,10):
x.append(i)
print x
print "______________________________________"
y = x * 10
x = "Hello World!"
print x
print "______________________________________"
print y
# What are X and Y?
===================================
#############
# Arithmetic
#############
4 + 4 == 8
3  5 == 2
16 / 2 == 8
16 * 4 == 64
3 % 2 == 1 # Modulus
# Long Int Conversion  Useful for function type mismatches  Not needed here.
100000000000000000000L + long(100) == 100000000000000000100L
======================
##########
# Strings
##########
a = "Hello"
b = "World!"
# Concatenation
a + " " + b == "Hello World!"
# Repetition and Concatenation
a * 3 + " " + b == "HelloHelloHello World!"
(a + " ") * 3 + b == "Hello Hello Hello World!"
# Indexing
b[2] == "r"
# Conversion of data to string  Sesame Street:
c = 7 # Backquote ` ` or str() operations
( a + " number " + `c` ) and ( a + " number " + str(c) ) == "Hello number 7"
============================
Python dice roll code example
#dice roll function (6sided by default)
import random
def roll(d=6):
return random.randint(1, d)
while 1 > 0 :
a=raw_input("enter number 16 : ")
b=int(a)
print ("entered :" , b)
c=roll()
print ("received :" , c)
if (c == b):
print ("you win ")
break
else :
print ("you loose " , b , " <> ", c)
print ("")
what does break do?
What is the use of random ?
======================
import random
def roll(d=6):
return random.randint(1, d)
while 1 > 0 :
a=raw_input("enter number 16 : ")
b=int(a)
print ("entered :" , b)
c=roll()
print ("received :" , c)
if (c == b):
print ("you win ")
break
else :
print ("you loose " , b , " <> ", c)
print ("")
what does break do?
What is the use of random ?
======================
Python Dictionaries and Lists Difference
#debugger example
print "This function creates a list."
def makelist():
a = [] # list
for i in range(1, 20):
a.append(i)
print "appending", i
print "now list", a
return a
def printlist(a):
for i in a:
print i,
b=makelist()
printlist(b)
#Dictionaries
#rock, paper, scissors game using dictionary
choice = raw_input("Enter s, r, or p: ")
results = {"s": "cut paper", "r": "crushes scissors", "p":
"covers rock"}
print choice, results[choice]
#
#
print "This function creates a list."
def makelist():
a = [] # list
for i in range(1, 20):
a.append(i)
print "appending", i
print "now list", a
return a
def printlist(a):
for i in a:
print i,
b=makelist()
printlist(b)
#Dictionaries
#rock, paper, scissors game using dictionary
choice = raw_input("Enter s, r, or p: ")
results = {"s": "cut paper", "r": "crushes scissors", "p":
"covers rock"}
print choice, results[choice]
#
#
Python Classes Revision
#class example
class Student:
def __init__(self, myname, myage): # note double underscores
self.myname = myname # take passed value to a var
self.myage = myage # take next value
def sayname(self): # take next function in class
print "Hello, my name is", self.myname
def sayage(self):
print "Hello, my age is", self.myage
def jump(self,jump): # the jump function
if (jump > 0) :
print "I am jumping up ", jump
else :
print "I am jumping down ", jump
name1 = Student("Amara", 17) # create object from class
name1.sayname() # print name
name1.sayage()
name1.jump(4) # move up 4
name1.jump( 4) # move down 4
class Student:
def __init__(self, myname, myage): # note double underscores
self.myname = myname # take passed value to a var
self.myage = myage # take next value
def sayname(self): # take next function in class
print "Hello, my name is", self.myname
def sayage(self):
print "Hello, my age is", self.myage
def jump(self,jump): # the jump function
if (jump > 0) :
print "I am jumping up ", jump
else :
print "I am jumping down ", jump
name1 = Student("Amara", 17) # create object from class
name1.sayname() # print name
name1.sayage()
name1.jump(4) # move up 4
name1.jump( 4) # move down 4
Python Lists : Code Examples for learning
print "This function creates a list."
def makelist():
a = []
for i in range(1, 20):
a.append(i)
print ("appending", i, ":", a)
return a
makelist()
How does this work?
hints
First you create and empty list and fill it later []
you add item one by one  it get added to last
Why lists are powerful than tuples
What is the advantage of dictioneries?
Can you have a tuple and a dictionary in a list?
Can you also add an object to it?
#building a list from another list
L1 = ['spa', 'spa', 'spa', 'beans', None, 'spa', 'spa']
L2 = []
for i in L1:
if i is not None:
L2.append(i)
print (L2)
#
#
def makelist():
a = []
for i in range(1, 20):
a.append(i)
print ("appending", i, ":", a)
return a
makelist()
How does this work?
hints
First you create and empty list and fill it later []
you add item one by one  it get added to last
Why lists are powerful than tuples
What is the advantage of dictioneries?
Can you have a tuple and a dictionary in a list?
Can you also add an object to it?
#building a list from another list
L1 = ['spa', 'spa', 'spa', 'beans', None, 'spa', 'spa']
L2 = []
for i in L1:
if i is not None:
L2.append(i)
print (L2)
#
#
What is the output of phyton from code
What is the output of phyton
# mile/kilometer conversion
for miles in range(10, 70, 10):
km = miles * 1.609
print "%d miles > %3.2f kilometers" % (miles, km)
#
Hints
range work among all numbers
multiplication by float number create float variable
%d digit %f float
=============
How do you call tiny function
def simplefunction(x):
print ("functions work!")
print ("You passed parameter", x)
z = x**2
print (x, "squared value =", z)
return z
Hints
functions need to be called form program to work
some functions need parameters
what error would you get if you call it
simplefunction()
or
simplefunction("Kandy")
======================
What happens here ?
#while loop example
countdown = 10
while countdown:
print countdown,
countdown = 1
print "blasted!"
#
explain each line to your self ?
how many times will the loop run ?
what is the value of countdown at last ?
# mile/kilometer conversion
for miles in range(10, 70, 10):
km = miles * 1.609
print "%d miles > %3.2f kilometers" % (miles, km)
#
Hints
range work among all numbers
multiplication by float number create float variable
%d digit %f float
=============
How do you call tiny function
def simplefunction(x):
print ("functions work!")
print ("You passed parameter", x)
z = x**2
print (x, "squared value =", z)
return z
Hints
functions need to be called form program to work
some functions need parameters
what error would you get if you call it
simplefunction()
or
simplefunction("Kandy")
======================
What happens here ?
#while loop example
countdown = 10
while countdown:
print countdown,
countdown = 1
print "blasted!"
#
explain each line to your self ?
how many times will the loop run ?
what is the value of countdown at last ?
Python Code Completion Exersize
පන්තියක සිසුන් විෂය තුනක් සඳහා ලබාගත් ලකුණු එක් එක් සිසුවාගේ නම සමග පහතදැක්වෙන අයුරු "input.text" නම් ගොනුවේ සටහන් කර ඇත.
Nimal, 20, 10, 30
Saman, 40, 60, 45
Mala, 22, 65, 75
එක් එක් සිසුවා විෂය තුන සඳහා ලබාගත් ලකුණුවල එකතුව හා මධ්යන්යය (Mean) පහත දැක්වෙන ආකාරයට ආදානය කළ යුතු යැයි සලකන්න.
1. Nimal 60 20.0
2. Saman 145 48.3
3. Mala 162 54.0
මේ සඳහා නිර්මාණය කළ අසම්පූර්ණ පයිතන් කේතයක් පහත දැක්වේ. මෙම කේතයේ සම්පූර්ණ ස්ථාන කඩ ඉරි මගින් දක්වා ඇත.
def total(marks):
#compute the total
total=0
for mark in marks
_ _ _ _ _ _ _ _ _
return total
f=open("inpit.text")
line=f.readline()
i= _ _ _ _ _ _ _ _ _ _
while(line ='')
record=line.strip('\n').split(",")
aggregate=total_ _ _ _ _ _ _ _ _ _
print i,_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
i +=1
line = _ _ _ _ _ _ _ _ _
f.close()
ඉහත කේතයට අදාළ ප්රතිදානය ලබාගැනීම සඳහා සුදුසු ලෙස සම්පූර්ණ කරන්න.
def total(marks): #compute the total
total=0
for mark in marks
total=total+marks
return total
f=open("input.text")
line=f.readline()
i=1
while(line <> '') :
record=line.split(",")
total=record[1]+record[2] + record[3]
aggregate=total/3
print ("%. %s %d, f%") % (i,record[1], total, aggregate)
i +=1
line =line=f.readline()
f.close()
=====
The Mean and the Median
100, 100, 130, 140, 150
To find the median, arrange values from smallest to largest.
If there is an odd number of values, the median is the middle value. If there is an even number of values, the median is the average of the two middle values.
130 is the middle value.
The mean is computed by adding all of the observations and dividing by the number of observations.
(100 + 100 + 130 + 140 + 150)/5 = 620/5 = 124
Population mean = μ = ΣX / N OR
Sample mean = x = Σx / n
Four friends take an IQ test. Their scores are 96, 100, 106, 114. Which of the following statements is true?
I. The mean is 103.
II. The mean is 104.
III. The median is 100.
IV. The median is 106.
(A) I only
(B) II only
(C) III only
(D) IV only
(E) None is true
Solution
The correct answer is (B).
Mean score = Σx / n = (96 + 100 + 106 + 114) / 4 = 104
Since there are an even number of scores (4), the median is the average of the two middle scores. Thus, the median is (100 + 106) / 2 = 103.

http://stattrek.com/lesson1/formulas.aspx
Nimal, 20, 10, 30
Saman, 40, 60, 45
Mala, 22, 65, 75
එක් එක් සිසුවා විෂය තුන සඳහා ලබාගත් ලකුණුවල එකතුව හා මධ්යන්යය (Mean) පහත දැක්වෙන ආකාරයට ආදානය කළ යුතු යැයි සලකන්න.
1. Nimal 60 20.0
2. Saman 145 48.3
3. Mala 162 54.0
මේ සඳහා නිර්මාණය කළ අසම්පූර්ණ පයිතන් කේතයක් පහත දැක්වේ. මෙම කේතයේ සම්පූර්ණ ස්ථාන කඩ ඉරි මගින් දක්වා ඇත.
def total(marks):
#compute the total
total=0
for mark in marks
_ _ _ _ _ _ _ _ _
return total
f=open("inpit.text")
line=f.readline()
i= _ _ _ _ _ _ _ _ _ _
while(line ='')
record=line.strip('\n').split(",")
aggregate=total_ _ _ _ _ _ _ _ _ _
print i,_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
i +=1
line = _ _ _ _ _ _ _ _ _
f.close()
ඉහත කේතයට අදාළ ප්රතිදානය ලබාගැනීම සඳහා සුදුසු ලෙස සම්පූර්ණ කරන්න.
def total(marks): #compute the total
total=0
for mark in marks
total=total+marks
return total
f=open("input.text")
line=f.readline()
i=1
while(line <> '') :
record=line.split(",")
total=record[1]+record[2] + record[3]
aggregate=total/3
print ("%. %s %d, f%") % (i,record[1], total, aggregate)
i +=1
line =line=f.readline()
f.close()
=====
The Mean and the Median
100, 100, 130, 140, 150
To find the median, arrange values from smallest to largest.
If there is an odd number of values, the median is the middle value. If there is an even number of values, the median is the average of the two middle values.
130 is the middle value.
The mean is computed by adding all of the observations and dividing by the number of observations.
(100 + 100 + 130 + 140 + 150)/5 = 620/5 = 124
Population mean = μ = ΣX / N OR
Sample mean = x = Σx / n
Four friends take an IQ test. Their scores are 96, 100, 106, 114. Which of the following statements is true?
I. The mean is 103.
II. The mean is 104.
III. The median is 100.
IV. The median is 106.
(A) I only
(B) II only
(C) III only
(D) IV only
(E) None is true
Solution
The correct answer is (B).
Mean score = Σx / n = (96 + 100 + 106 + 114) / 4 = 104
Since there are an even number of scores (4), the median is the average of the two middle scores. Thus, the median is (100 + 106) / 2 = 103.

http://stattrek.com/lesson1/formulas.aspx
Code Correction
පහත පයිතන් ක්රමලේඛ අතුරින් දෝෂ රහිත ක්රමලේඛ මොනවාදැයි දක්වන්න. දෝෂ රහිත ක්රමලේඛ ක්රියාත්මක කිරීමේදී ලැබෙන ප්රතිදාන මොනවාදැයි දක්වන්න.
දෝෂ සහිත ක්රමලේඛ නිදොස් කර දක්වා, එම නිදොස් ක්රමලේඛ ක්රියාත්මක කිරීමේදී ලැබෙන ප්රතිදාන මොනවාදැයි සඳහන් කරන්න.
animals=['Dog','Rat','Cat']
animals.sort()
for animal in animals:
print i,animal.strip(),len(animal)
i t=1
animals=['Dog','Rat','Cat']
animals.sort()
for animal in animals:
i=len(animal)
t=animal.strip(),
print (t)
def times(a):
for i in range(1,12):
print a,' x ', i,' = ',a*i
times(5)
def times(a):
for i in range(1,12):
print (a, i,' = ',a*i)
times(5)
===
This module defines some constants useful for checking character classes and some useful string functions. See the module re for string functions based on regular expressions.
The constants defined in this module are:
The module also defines two mathematical constants:
දෝෂ සහිත ක්රමලේඛ නිදොස් කර දක්වා, එම නිදොස් ක්රමලේඛ ක්රියාත්මක කිරීමේදී ලැබෙන ප්රතිදාන මොනවාදැයි සඳහන් කරන්න.
animals=['Dog','Rat','Cat']
animals.sort()
for animal in animals:
print i,animal.strip(),len(animal)
i t=1
animals=['Dog','Rat','Cat']
animals.sort()
for animal in animals:
i=len(animal)
t=animal.strip(),
print (t)
def times(a):
for i in range(1,12):
print a,' x ', i,' = ',a*i
times(5)
def times(a):
for i in range(1,12):
print (a, i,' = ',a*i)
times(5)
===
string  Common string operations
This module defines some constants useful for checking character classes and some useful string functions. See the module re for string functions based on regular expressions.
The constants defined in this module are:
 ascii_letters
 The concatenation of the ascii_lowercase and ascii_uppercase constants described below. This value is not localedependent.
 ascii_lowercase
 The lowercase letters
'abcdefghijklmnopqrstuvwxyz'
. This value is not localedependent and will not change.
 ascii_uppercase
 The uppercase letters
'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
. This value is not localedependent and will not change.
 digits
 The string
'0123456789'
.
 hexdigits
 The string
'0123456789abcdefABCDEF'
.
 letters
 The concatenation of the strings lowercase and uppercase described below. The specific value is localedependent, and will be updated when locale.setlocale() is called.
 lowercase
 A string containing all the characters that are considered lowercase letters. On most systems this is the string
'abcdefghijklmnopqrstuvwxyz'
. Do not change its definition  the effect on the routines upper() and swapcase() is undefined. The specific value is localedependent, and will be updated when locale.setlocale() is called.
 octdigits
 The string
'01234567'
.
 punctuation
 String of ASCII characters which are considered punctuation characters in the "C" locale.
 printable
 String of characters which are considered printable. This is a combination of digits, letters, punctuation, and whitespace.
 uppercase
 A string containing all the characters that are considered uppercase letters. On most systems this is the string
'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
. Do not change its definition  the effect on the routines lower() and swapcase() is undefined. The specific value is localedependent, and will be updated when locale.setlocale() is called.
 whitespace
 A string containing all characters that are considered whitespace. On most systems this includes the characters space, tab, linefeed, return, formfeed, and vertical tab. Do not change its definition  the effect on the routines strip() and split() is undefined.

atof( s)  Deprecated since release 2.0. Use the float() builtin function.Convert a string to a floating point number. The string must have the standard syntax for a floating point literal in Python, optionally preceded by a sign ("+" or ""). Note that this behaves identical to the builtin function float() when passed a string. Note: When passing in a string, values for NaN and Infinity may be returned, depending on the underlying C library. The specific set of strings accepted which cause these values to be returned depends entirely on the C library and is known to vary.

atoi( s[, base])  Deprecated since release 2.0. Use the int() builtin function.Convert string s to an integer in the given base. The string must consist of one or more digits, optionally preceded by a sign ("+" or ""). The base defaults to 10. If it is 0, a default base is chosen depending on the leading characters of the string (after stripping the sign): "0x" or "0X" means 16, "0" means 8, anything else means 10. If base is 16, a leading "0x" or "0X" is always accepted, though not required. This behaves identically to the builtin function int() when passed a string. (Also note: for a more flexible interpretation of numeric literals, use the builtin function eval() .)

atol( s[, base])  Deprecated since release 2.0. Use the long() builtin function.Convert string s to a long integer in the given base. The string must consist of one or more digits, optionally preceded by a sign ("+" or ""). The base argument has the same meaning as for atoi(). A trailing "l" or "L" is not allowed, except if the base is 0. Note that when invoked without base or with base set to 10, this behaves identical to the builtin function long() when passed a string.

capitalize( word)  Return a copy of word with only its first character capitalized.

capwords( s)  Split the argument into words using split(), capitalize each word using capitalize(), and join the capitalized words using join(). Note that this replaces runs of whitespace characters by a single space, and removes leading and trailing whitespace.

expandtabs( s[, tabsize])  Expand tabs in a string, i.e. replace them by one or more spaces, depending on the current column and the given tab size. The column number is reset to zero after each newline occurring in the string. This doesn't understand other nonprinting characters or escape sequences. The tab size defaults to 8.

find( s, sub[, start[,end]])  Return the lowest index in s where the substring sub is found such that sub is wholly contained in
s[start:end]
. Return1
on failure. Defaults for start and end and interpretation of negative values is the same as for slices.

rfind( s, sub[, start[, end]])  Like find() but find the highest index.

index( s, sub[, start[, end]])  Like find() but raise ValueError when the substring is not found.

rindex( s, sub[, start[, end]])  Like rfind() but raise ValueError when the substring is not found.

count( s, sub[, start[, end]])  Return the number of (nonoverlapping) occurrences of substring sub in string
s[start:end]
. Defaults for start and end and interpretation of negative values are the same as for slices.

lower( s)  Return a copy of s, but with upper case letters converted to lower case.

maketrans( from, to)  Return a translation table suitable for passing to translate() or regex.compile(), that will map each character in from into the character at the same position in to; from and to must have the same length. Warning: Don't use strings derived from lowercase and uppercase as arguments; in some locales, these don't have the same length. For case conversions, always use lower() and upper().

split( s[, sep[, maxsplit]])  Return a list of the words of the string s. If the optional second argument sep is absent or
None
, the words are separated by arbitrary strings of whitespace characters (space, tab, newline, return, formfeed). If the second argument sep is present and notNone
, it specifies a string to be used as the word separator. The returned list will then have one more item than the number of nonoverlapping occurrences of the separator in the string. The optional third argument maxsplit defaults to 0. If it is nonzero, at most maxsplit number of splits occur, and the remainder of the string is returned as the final element of the list (thus, the list will have at mostmaxsplit+1
elements).

splitfields( s[, sep[, maxsplit]])  This function behaves identically to split(). (In the past, split() was only used with one argument, while splitfields() was only used with two arguments.)

join( words[, sep])  Concatenate a list or tuple of words with intervening occurrences of sep. The default value for sep is a single space character. It is always true that "string.join(string.split(s, sep), sep)" equals s.

joinfields( words[, sep])  This function behaves identically to join(). (In the past, join() was only used with one argument, while joinfields() was only used with two arguments.) Note that there is no joinfields() method on string objects; use the join() method instead.

lstrip( s[, chars])  Return a copy of the string with leading characters removed. If chars is omitted or
None
, whitespace characters are removed. If given and notNone
, chars must be a string; the characters in the string will be stripped from the beginning of the string this method is called on. Changed in version 2.2.3: The chars parameter was added. The chars parameter cannot be passed in earlier 2.2 versions.

rstrip( s[, chars])  Return a copy of the string with trailing characters removed. If chars is omitted or
None
, whitespace characters are removed. If given and notNone
, chars must be a string; the characters in the string will be stripped from the end of the string this method is called on. Changed in version 2.2.3: The chars parameter was added. The chars parameter cannot be passed in 2.2 versions.

strip( s[, chars])  Return a copy of the string with leading and trailing characters removed. If chars is omitted or
None
, whitespace characters are removed. If given and notNone
, chars must be a string; the characters in the string will be stripped from the both ends of the string this method is called on. Changed in version 2.2.3: The chars parameter was added. The chars parameter cannot be passed in earlier 2.2 versions.

swapcase( s)  Return a copy of s, but with lower case letters converted to upper case and vice versa.

translate( s, table[, deletechars])  Delete all characters from s that are in deletechars (if present), and then translate the characters using table, which must be a 256character string giving the translation for each character value, indexed by its ordinal.

upper( s)  Return a copy of s, but with lower case letters converted to upper case.

ljust( s, width) 
rjust( s, width) 
center( s, width)  These functions respectively leftjustify, rightjustify and center a string in a field of given width. They return a string that is at least width characters wide, created by padding the string s with spaces until the given width on the right, left or both sides. The string is never truncated.

zfill( s, width)  Pad a numeric string on the left with zero digits until the given width is reached. Strings starting with a sign are handled correctly.

replace( str, old, new[, maxsplit])  Return a copy of string str with all occurrences of substring old replaced by new. If the optional argument maxsplit is given, the first maxsplit occurrences are replaced.
math  Mathematical functions
This module is always available. It provides access to the mathematical functions defined by the C standard. These functions cannot be used with complex numbers; use the functions of the same name from the cmath module if you require support for complex numbers. The distinction between functions which support complex numbers and those which don't is made since most users do not want to learn quite as much mathematics as required to understand complex numbers. Receiving an exception instead of a complex result allows earlier detection of the unexpected complex number used as a parameter, so that the programmer can determine how and why it was generated in the first place. The following functions are provided by this module. Except when explicitly noted otherwise, all return values are floats: 
acos( x)  Return the arc cosine of x.

asin( x)  Return the arc sine of x.

atan( x)  Return the arc tangent of x.

atan2( y, x)  Return
atan(y / x)
.

ceil( x)  Return the ceiling of x as a float.

cos( x)  Return the cosine of x.

cosh( x)  Return the hyperbolic cosine of x.

degrees( x)  Converts angle x from radians to degrees.

exp( x)  Return
e**x
.

fabs( x)  Return the absolute value of x.

floor( x)  Return the floor of x as a float.

fmod( x, y)  Return
fmod(x, y)
, as defined by the platform C library. Note that the Python expressionx % y
may not return the same result.

frexp( x)  Return the mantissa and exponent of x as the pair
(m, e)
. m is a float and e is an integer such thatx == m * 2**e
. If x is zero, returns(0.0, 0)
, otherwise0.5 <= abs(m) < 1
.

hypot( x, y)  Return the Euclidean distance,
sqrt(x*x + y*y)
.

ldexp( x, i)  Return
x * (2**i)
.

log( x[, base])  Returns the logarithm of x to the given base. If the base is not specified, returns the natural logarithm of x. Changed in version 2.3: base argument added.

log10( x)  Return the base10 logarithm of x.

modf( x)  Return the fractional and integer parts of x. Both results carry the sign of x. The integer part is returned as a float.

pow( x, y)  Return
x**y
.

radians( x)  Converts angle x from degrees to radians.

sin( x)  Return the sine of x.

sinh( x)  Return the hyperbolic sine of x.

sqrt( x)  Return the square root of x.

tan( x)  Return the tangent of x.

tanh( x)  Return the hyperbolic tangent of x.
The module also defines two mathematical constants:
 pi
 The mathematical constant pi.
 e
 The mathematical constant e.
Interpreters and Compilers Differences
භාෂා සම්පාදකවල (Compilers) හා අර්ථ වින්යාසකවල(Interpreters) මූලික කාර්යය කුමක්දැයි දක්වා, ඒවා භාවිතයේදී ලැබෙන වාසි සහ අවාසි සන්සන්දනය කරන්න.
Compiler vs Interpreter
Both basically serve the same purpose.
Convert one level of language to another level.
Compiler converts the high level instructions into machine language.
Interpreter converts the high level instruction into an intermediate form, and the instructions are executed.
Compiler
Convert to binary form understood by the computer.
The complier programs are evolving in this way which improves their ease of use.
Compliers can be multiple or multistage pass. The first pass can convert the high level language into a language that is closer to computer language. Then the further passes can convert it into final stage for the purpose of execution.
The advantage of using an interpreter is that the high level instruction does not goes through compilation stage which can be a time consuming method.
Almost all high level programming languages have compilers and interpreters.
Difference between compiler and interpreter
• A complier converts the high level instruction into machine language
• Interpreter converts the high level instruction into an intermediate form.
• Before execution, entire program is executed by the compiler
interpreter translates a line then executes it and so on.
• List of errors is created by the compiler after the compilation process
• interpreter stops translating after the first error.
• Compiler creates an independent executable file
• interpreter is required by an interpreted program each time.
Assembler
Dual Purpose
Java
C++
Python
VB
ASP.NET
Interpreter
PHP
ASP
Java Script
Compiler vs Interpreter
Both basically serve the same purpose.
Convert one level of language to another level.
Compiler converts the high level instructions into machine language.
Interpreter converts the high level instruction into an intermediate form, and the instructions are executed.
Compiler
Convert to binary form understood by the computer.
The complier programs are evolving in this way which improves their ease of use.
Compliers can be multiple or multistage pass. The first pass can convert the high level language into a language that is closer to computer language. Then the further passes can convert it into final stage for the purpose of execution.
The advantage of using an interpreter is that the high level instruction does not goes through compilation stage which can be a time consuming method.
Almost all high level programming languages have compilers and interpreters.
Difference between compiler and interpreter
• A complier converts the high level instruction into machine language
• Interpreter converts the high level instruction into an intermediate form.
• Before execution, entire program is executed by the compiler
interpreter translates a line then executes it and so on.
• List of errors is created by the compiler after the compilation process
• interpreter stops translating after the first error.
• Compiler creates an independent executable file
• interpreter is required by an interpreted program each time.
Assembler
Dual Purpose
Java
C++
Python
VB
ASP.NET
Interpreter
PHP
ASP
Java Script
Flow Chart to Python Code
(python)
x=1
total=0
while x<=10 :
math=input("enter marks")
x=x+1
total=total+math
avg=total/x1
if (avg > 50):
print "Good"
else:
print "Bad"
Python Code
x=1
total=0
while x<=10 :
xmath=int(input("enter marks"))
type(xmath)
x=x+1
total=total+xmath
avg=(total/x1)
if (avg > 50):
print ("Good")
else:
print ("Bad")
======================
ffor x in "pythonprogramming":
print(x)
if x=='':
break
print x
What is your explanation  will this work ? on indentinng
what are the output of following codes ?
for x in "pythonprogramming":
print(x)
if x=='':
break
print (x)
for x in "pythonprogramming":
print(x)
if x=='':
continue
print (x)
x=1
total=0
while x<=10 :
math=input("enter marks")
x=x+1
total=total+math
avg=total/x1
if (avg > 50):
print "Good"
else:
print "Bad"
Python Code
x=1
total=0
while x<=10 :
xmath=int(input("enter marks"))
type(xmath)
x=x+1
total=total+xmath
avg=(total/x1)
if (avg > 50):
print ("Good")
else:
print ("Bad")
======================
ffor x in "pythonprogramming":
print(x)
if x=='':
break
print x
What is your explanation  will this work ? on indentinng
what are the output of following codes ?
for x in "pythonprogramming":
print(x)
if x=='':
break
print (x)
for x in "pythonprogramming":
print(x)
if x=='':
continue
print (x)
පහත දැක්වෙන පයිතන් ක්රමලේඛය සලකා බලන්න:
පහත දැක්වෙන පයිතන් ක්රමලේඛය සලකා බලන්න:
from date import date
class dtcheck:
def_init_(self,y,m,d):
self.now=date.today()
self.dob=date(y,m,d)
self.age=self.now  self.dob
def printage(self):
return "your age %d" % ((self.age.days)/365)
මෙහි දැක්වෙන්නේ උපන් දිනය ලබාදීමෙන් පසු වයස අවුරුදුවලින් ප්රතිපානය කිරීම සඳහා සැකසූ පන්ති මොඩියුලයකි. මෙම මොඩියුලය "dcheck.py" යන ලිපිගොනු නාමයෙන් පයිතන් ක්රමලේඛයක් ලෙස සුරැකී ඇත. මෙම පන්ති මොඩියුලයෙන් වස්තුවක් (object) නිර්මාණය කර, එයට ආදානය ලබාදෙමින් ප්රතිදානය ලබාගැනීමට භාවිත කළ හැකි නිවැරදිථ පයිතන් මොඩියුලය කුමක් ද?
import dcheck
w=dcheck.dtcheck(1976,11,10)
result=w.printage()
print w
import dcheck
w.dcheck(1976/11/10)
result=w.printage()
print result
import dcheck
w.dtcheck.dcheck(1976,11,10)
result=w.printage()
print result
w=dcheck.dcheck(1976/11/10)
result=w.printage()
print result
Python 3.x code
from datetime import date
class dtcheck:
def __init__(self,y,m,d):
self.now=date.today()
self.dob=date(y,m,d)
self.age=self.now  self.dob
def printage(self):
return "your age %d"%((self.age.days)/365)
import dcheck
u=dcheck.dtcheck(1976,11,10)
print (u.printage())
================
# Import module hello
import hello # Now you can call defined function
hello.print_func("Dinuka")
Hello : Dinuka
UNIX system:
#!/usr/bin/python
=================
A namespace is a dictionary of variable names (keys) and their corresponding objects (values).
Python can access variables in a local namespace and in the global namespace. I
if a local and a global variable have the same name, the local variable shadows the global variable.
Each function has its own local namespace.
Python makes guesses on whether variables are local or global.
It assumes that any variable assigned a value in a function is local.
To assign a value to a global variable within a function,
use global VarName which tells Python that VarName is a global variable.
what happens ? if # global Honey uncommented like
Similar way we have another two files having different functions with the same name as above:
After you've added these lines to __init__.py, you have all of these classes available when you've imported the Phone package:
This would produce following result:
from date import date
class dtcheck:
def_init_(self,y,m,d):
self.now=date.today()
self.dob=date(y,m,d)
self.age=self.now  self.dob
def printage(self):
return "your age %d" % ((self.age.days)/365)
මෙහි දැක්වෙන්නේ උපන් දිනය ලබාදීමෙන් පසු වයස අවුරුදුවලින් ප්රතිපානය කිරීම සඳහා සැකසූ පන්ති මොඩියුලයකි. මෙම මොඩියුලය "dcheck.py" යන ලිපිගොනු නාමයෙන් පයිතන් ක්රමලේඛයක් ලෙස සුරැකී ඇත. මෙම පන්ති මොඩියුලයෙන් වස්තුවක් (object) නිර්මාණය කර, එයට ආදානය ලබාදෙමින් ප්රතිදානය ලබාගැනීමට භාවිත කළ හැකි නිවැරදිථ පයිතන් මොඩියුලය කුමක් ද?
import dcheck
w=dcheck.dtcheck(1976,11,10)
result=w.printage()
print w
import dcheck
w.dcheck(1976/11/10)
result=w.printage()
print result
import dcheck
u=dcheck.dtcheck(1976,11,10)
print u.printage()
u=dcheck.dtcheck(1976,11,10)
print u.printage()
import dcheck
w.dtcheck.dcheck(1976,11,10)
result=w.printage()
print result
w=dcheck.dcheck(1976/11/10)
result=w.printage()
print result
Python 3.x code
from datetime import date
class dtcheck:
def __init__(self,y,m,d):
self.now=date.today()
self.dob=date(y,m,d)
self.age=self.now  self.dob
def printage(self):
return "your age %d"%((self.age.days)/365)
import dcheck
u=dcheck.dtcheck(1976,11,10)
print (u.printage())
================
The import Statement:
You can use any Python source file as a module by executing an import statement in some other Python source file. import has the following syntax:import module1[, module2[,... moduleN] 
# Import module hello
import hello # Now you can call defined function
hello.print_func("Dinuka")
Hello : Dinuka
The from...import * Statement:
It is also possible to import all names from a modulefrom modname import * 
The PYTHONPATH Variable:
The PYTHONPATH is an environment variable, consist list of directories.set PYTHONPATH=c:\python20\lib; 
set PYTHONPATH=/usr/local/lib/python 
#!/usr/bin/python
=================
Namespaces and Scoping:
Variables are names map to objects.A namespace is a dictionary of variable names (keys) and their corresponding objects (values).
Python can access variables in a local namespace and in the global namespace. I
if a local and a global variable have the same name, the local variable shadows the global variable.
Each function has its own local namespace.
Python makes guesses on whether variables are local or global.
It assumes that any variable assigned a value in a function is local.
To assign a value to a global variable within a function,
use global VarName which tells Python that VarName is a global variable.
#!/usr/bin/python Honey = 2000 def AddHoney(): # Uncomment the following line to fix the code: # global Honey Honey = Honey + 1 print Honey AddHoney() print Honey 
what happens ? if # global Honey uncommented like
global Honey The Global variable get updated
=================
Packages in Python:
A package is a hierarchical file directory structure that defines a single Python application environment that consists of modules and subpackages and subsubpackages,Example:
Consider a file Mobs.py available in Phone directory. This file has following line of source code:#!/usr/bin/python def Mobs(): print "I'm a mobile phone" 
 Phone/Isdn.py file having function Isdn()
 Phone/G3.py file having function G3()
 Phone/__init__.py
from Pots import Pots from Isdn import Isdn from G3 import G3 
#!/usr/bin/python # Now import your Phone Package. import Phone Phone.Mobs() Phone.Isdn() Phone.G3() 
I'm a mobile phone I'm 3G Phone I'm ISDN Phone 
Python Operators
3 = 1+2
in 1 + 2 =3 , 1 and 2 are called operands and + is called operator.
 Arithmetic Operators +,  , /
 Comparision Operators <>
 Logical (or Relational) Operators or and
 Assignment Operators =
 Conditional (or ternary) Operators
Python Arithmetic Operators:
Assume variable a holds 10 and variable b holds 20 then:Operator  Description  Example 

+  Addition  Adds values on either side of the operator  a + b will give 30 
  Subtraction  Subtracts right hand operand from left hand operand  a  b will give 10 
*  Multiplication  Multiplies values on either side of the operator  a * b will give 200 
/  Division  Divides left hand operand by right hand operand  b / a will give 2 
%  Modulus  Divides left hand operand by right hand operand and returns remainder  b % a will give 0 
**  Exponent  Performs exponential (power) calculation on operators  a**b will give 10 to the power 20 
//  Floor Division  The division of operands where the result is the quotient in which the digits after the decimal point are removed.  9//2 is equal to 4 and 9.0//2.0 is equal to 4.0 
Python Comparison Operators:
Assume variable a holds 10 and variable b holds 20 then:Operator  Description  Example 

==  Checks if the value of two operands are equal or not, if yes then condition becomes true.  (a == b) is not true. 
!=  Checks if the value of two operands are equal or not, if values are not equal then condition becomes true.  (a != b) is true. 
<>  Checks if the value of two operands are equal or not, if values are not equal then condition becomes true.  (a <> b) is true. This is similar to != operator. 
>  Checks if the value of left operand is greater than the value of right operand, if yes then condition becomes true.  (a > b) is not true. 
<  Checks if the value of left operand is less than the value of right operand, if yes then condition becomes true.  (a < b) is true. 
>=  Checks if the value of left operand is greater than or equal to the value of right operand, if yes then condition becomes true.  (a >= b) is not true. 
<=  Checks if the value of left operand is less than or equal to the value of right operand, if yes then condition becomes true.  (a <= b) is true. 
Python Assignment Operators:
Python Logical Operators:
and  Logical AND operator. If both the operands are true then condition becomes true.  (a and b) is true. 
or  Logical OR Operator. I f any of the two operands are non zero then then condition becomes true.  (a or b) is true. 
not  Logical NOT Operator. Use to reverses the logical state of its operand. If a condition is true then Logical NOT operator will make false.  not(a and b) is false. 
Python Membership Operators:
Operator  Description  Example 

in  Evaluates to true if it finds a variable in the specified sequence and false otherwise.  x in y, here in results in a 1 if x is a member of sequence y. 
not in  Evaluates to true if it does not finds a variable in the specified sequence and false otherwise.  x not in y, here not in results in a 1 if x is a member of sequence y. 
Python Assignment Operators:
Assume variable a holds 10 and variable b holds 20 then:Operator  Description  Example 

=  Simple assignment operator, Assigns values from right side operands to left side operand  c = a + b will assigne value of a + b into c 
+=  Add AND assignment operator, It adds right operand to the left operand and assign the result to left operand  c += a is equivalent to c = c + a 
=  Subtract AND assignment operator, It subtracts right operand from the left operand and assign the result to left operand  c = a is equivalent to c = c  a 
*=  Multiply AND assignment operator, It multiplies right operand with the left operand and assign the result to left operand  c *= a is equivalent to c = c * a 
/=  Divide AND assignment operator, It divides left operand with the right operand and assign the result to left operand  c /= a is equivalent to c = c / a 
%=  Modulus AND assignment operator, It takes modulus using two operands and assign the result to left operand  c %= a is equivalent to c = c % a 
**=  Exponent AND assignment operator, Performs exponential (power) calculation on operators and assign value to the left operand  c **= a is equivalent to c = c ** a 
//=  Floor Dividion and assigns a value, Performs floor division on operators and assign value to the left operand  c //= a is equivalent to c = c // a 
Python Comparison Operators:
Assume variable a holds 10 and variable b holds 20 then:Operator  Description  Example 

==  Checks if the value of two operands are equal or not, if yes then condition becomes true.  (a == b) is not true. 
!=  Checks if the value of two operands are equal or not, if values are not equal then condition becomes true.  (a != b) is true. 
<>  Checks if the value of two operands are equal or not, if values are not equal then condition becomes true.  (a <> b) is true. This is similar to != operator. 
>  Checks if the value of left operand is greater than the value of right operand, if yes then condition becomes true.  (a > b) is not true. 
<  Checks if the value of left operand is less than the value of right operand, if yes then condition becomes true.  (a < b) is true. 
>=  Checks if the value of left operand is greater than or equal to the value of right operand, if yes then condition becomes true.  (a >= b) is not true. 
<=  Checks if the value of left operand is less than or equal to the value of right operand, if yes then condition becomes true.  (a <= b) is true. 
Python Arithmetic Operators:
Assume variable a holds 10 and variable b holds 20 then:Operator  Description  Example 

+  Addition  Adds values on either side of the operator  a + b will give 30 
  Subtraction  Subtracts right hand operand from left hand operand  a  b will give 10 
*  Multiplication  Multiplies values on either side of the operator  a * b will give 200 
/  Division  Divides left hand operand by right hand operand  b / a will give 2 
%  Modulus  Divides left hand operand by right hand operand and returns remainder  b % a will give 0 
**  Exponent  Performs exponential (power) calculation on operators  a**b will give 10 to the power 20 
//  Floor Division  The division of operands where the result is the quotient in which the digits after the decimal point are removed.  9//2 is equal to 4 and 9.0//2.0 is equal to 4.0 
Python Bitwise Operators:
Bitwise operator works on bits and perform bit by bit operation.Assume if a = 60; and b = 13; Now in binary format they will be as follows:
a = 0011 1100
b = 0000 1101

a&b = 0000 1100
ab = 0011 1101
a^b = 0011 0001
~a = 1100 0011
There are following Bitwise operators supported by Python language
Operator  Description  Example 

&  Binary AND Operator copies a bit to the result if it exists in both operands.  (a & b) will give 12 which is 0000 1100 
  Binary OR Operator copies a bit if it exists in eather operand.  (a  b) will give 61 which is 0011 1101 
^  Binary XOR Operator copies the bit if it is set in one operand but not both.  (a ^ b) will give 49 which is 0011 0001 
~  Binary Ones Complement Operator is unary and has the efect of 'flipping' bits.  (~a ) will give 60 which is 1100 0011 
<<  Binary Left Shift Operator. The left operands value is moved left by the number of bits specified by the right operand.  a << 2 will give 240 which is 1111 0000 
>>  Binary Right Shift Operator. The left operands value is moved right by the number of bits specified by the right operand.  a >> 2 will give 15 which is 0000 1111 
Python syntax examples
පහත දැක්වෙන පයිතන් ප්රකාශ සලකා බලන්න:
A  s="It's correct"
B  x=y=z=2.5
C  x,y,z=1,2.3,'string'
D  #This is not correct
E  a=['string',123]
F  b=5
while 4<=b>10:
b+=1
G  for x in range(0,12,3):
print x
H  a={'a':'b',4:40}
I  def fun1(a,b=4,l=[]):
return b*a
==================
Keywords contain lowercase letters only.
a holds 'Hello' and b holds 'Python' then:
This will produce following result:
Unicode String:
This would print following result:
while (count < 9):
A  s="It's correct"
B  x=y=z=2.5
C  x,y,z=1,2.3,'string'
D  #This is not correct
E  a=['string',123]
F  b=5
while 4<=b>10:
b+=1
G  for x in range(0,12,3):
print x
H  a={'a':'b',4:40}
I  def fun1(a,b=4,l=[]):
return b*a
==================
Reserved Words:
The following list shows the reserved words in Python. These reserved words may not be used as constant or variable or any other identifier names.Keywords contain lowercase letters only.
and  exec  not 
assert  finally  or 
break  for  pass 
class  from  
continue  global  raise 
def  if  return 
del  import  try 
elif  in  while 
else  is  with 
except  lambda  yield 
MultiLine Statements:
Statements in Python typically end with a new line. Python does, however, allow the use of the line continuation character (\) to denote that the line should continue. For example:total = item_one + \ item_two + \ item_three word = 'word' sentence = "isn't this a sentence." paragraph = """This is a paragraph. It is made up of multiple lines and sentences.""" paragraph = '''This is a paragraph. It is made up of multiple lines and sentences.''' 
# This is a comment. # This is a comment, too. raw_input("\n\nPress the enter key to exit.")
input("\n\nPress the enter key to exit.")
print("Press the enter key to exit") # Python 3.x
print "Press the enter key to exit" # Python 2.x
var1 = 1
var2 = 10
del var1, var2
Strings
var1 = 'Hello World!' var2 = "Python Programming" print "var1[0]: ", var1[0] print "var2[1:5]: ", var2[1:5] var1 = 'Hello World!' print "Updated String : ", var1[:6] + 'Python'
\n  0x0a  Newline 
print ("My name is %s and weight is %d kg!" % ('Sinali', 21) 
My name is Zara and weight is 21 kg! 
Format Symbol  Conversion 

%c  character 
%s  string conversion via str() prior to formatting 
%i  signed decimal integer 
%d  signed decimal integer 
%u  unsigned decimal integer 
%o  octal integer 
%x  hexadecimal integer (lowercase letters) 
%X  hexadecimal integer (UPPERcase letters) 
%e  exponential notation (with lowercase 'e') 
%E  exponential notation (with UPPERcase 'E') 
%f  floating point real number 
%g  the shorter of %f and %e 
%G  the shorter of %f and %E 
Unicode String:
print u'Hello, world!' 
Hello, world! 
count = 0
while (count < 9):
print 'The count is:', count
count = count + 1
print "Good bye!"
for letter in 'Python': # First Example if letter == 'h': break print 'Current Letter :', letter var = 10 # Second Example while var > 0: print 'Current variable value :', var var = var 1 if var == 5: break print "Good bye!" a=Hello b=Python
a + b will give HelloPython
a*2 will give HelloHello
a[1] will give e
[1:4] will give ell
H in a will give 1
M not in a will give 1
print r'\n' prints \n and print R'\n' prints \n
Python If then else
කොටුව තුළ දීඇති පයිතන් ක්රමලේඛයේ ප්රතිදානය කුමක් ද?
j=10
y=4
if j<y or j!=4:
j=y
print j
else:
y*=j
print y
(1) 4
(2) 6
(3) 10
(4) 14
(5) 40
Python 3.0
j=10
y=4
if ((j<y) or (j!=4)):
j=y
print (j)
else:
y*=j
print (y)
==================
0 Integer zero 0
0 Floating point zero
"" Empty strings
{} Empty dictionaries
[] Empty lists
() Empty tuples
j=10
y=4
if j<y or j!=4:
j=y
print j
else:
y*=j
print y
(1) 4
(2) 6
(3) 10
(4) 14
(5) 40
Python 3.0
j=10
y=4
if ((j<y) or (j!=4)):
j=y
print (j)
else:
y*=j
print (y)
==================
if, elif, and else program branches
mark=float(raw_input("Please enter a mark")) if mark >= 40: print "You passed." print "Well done." else: print "You failed." print "too bad."
age = 17 if age > 18: print "Driving licence issued" else: print "Driving licence not permitted"
if (age >= 12) or (age < 18)): print "teen"
else :
if (age < 12) :
print "kid" else: print "adult
Comparing data valuesNone The null object
0 Integer zero 0
0 Floating point zero
"" Empty strings
{} Empty dictionaries
[] Empty lists
() Empty tuples
magic=input("Enter No ? ") if not (magic == 8 or magic == 9 or magic ==10 ) : print '"Time for Tea", said Boss ' else: print '"No Tea !" said Boss'
Python Order of operations
r=11; y=2.5; c=4 වශයෙන් r, y, c විචල්යවලට අගය පවරා ඇත.
ඒ අනුව, r%3*c+10/y යන පයිතන් ප්රකාශයේ නිවැරත්ථ අගය කුමක් ද?
(1) 6.2 (2) 8.0 (3) 12.0 (4) 24.0 (5) 40.0
The order of operations
r%3*c+10/y
((r% 3)*c)+(10/y)
((11% 3)*4)+(10/2.5)
(2*4)+(4)
12
All operators
75 % 4 = 3 (4*18 = 72; remainder is 3)
100  3 = 97
ඒ අනුව, r%3*c+10/y යන පයිතන් ප්රකාශයේ නිවැරත්ථ අගය කුමක් ද?
(1) 6.2 (2) 8.0 (3) 12.0 (4) 24.0 (5) 40.0
command  name  example  output 
+  Addition  4+5  9 
  Subtraction  85  3 
*  Multiplication  4*5  20 
/  Division  19/3  6 
%  Remainder  19%3  5 
**  Exponent  2**4  16 
The order of operations
 parentheses ()
 exponents **
 multiplication *, division \, and remainder %
 addition + and subtraction 
r%3*c+10/y
((r% 3)*c)+(10/y)
((11% 3)*4)+(10/2.5)
(2*4)+(4)
12
All operators
+  * ** / // %
<< >> &  ^ ~
< > <= >= == !=
100  25 * 3 % 4 the result is 97 how?
25*3 = 7575 % 4 = 3 (4*18 = 72; remainder is 3)
100  3 = 97
Operator  Description  Example 

+,   Addition, Subtraction  10 3 
*, /, %  Multiplication, Division, Modulo  27 % 7 Result: 6 
//  Truncation Division (also known as floordivision) The result of the division is truncated to an integer. Works for integers and floatingpoint numbers as well  27 % 7 Result: 6 
+x, x  Unary minus and Unary plus (Algebraic signs)  3 
~x  Bitwise negation  ~3  4 Result: 8 
**  Exponentiation  10 ** 3 Result: 1000 
or, and, not  Boolean Or, Boolean And, Boolean Not  (a or b) and c 
in  "Element of"  1 in [3, 2, 1] 
<, <=, >, >=, !=, ==  The usual comparison operators  2 <= 3 
, &, ^  Bitwise Or, Bitwise And, Bitwise XOR  6 ^ 3 
<<, >>  Shift Operatoren  6 << 3 
Python Formating Strings
#program to convert Celsius Temperature to Fahrenheit
c=input ('Enter Temperature in Celsius:')
f=c*9/5.0+32
print "Fahrenheit %d" %f
දී ඇති ක්රමලේඛය දෝෂ සහිත ය. අපේක්ෂිත ප්රතිදානය ලබා ගැනීම සඳහා එය නිවැරදි විය යුත්තේ පහත සඳහන් කුමන ආකාරයට ද ?
1. #program to convert Celsius Temperature to Fahrenheit යන පේළිය ඉවත් කිරීම
2. c= input('Enter Temperature in Celsius:') පේළිය cinput('Enter Temperature in Celsius.') ලෙස වෙනස් කිරීම
3. F=c*9/5.0+32 පේළිය f=c*9.0/5.0+32 ලෙස වෙනස් කිරීම
4. print "Fahrenheit %d" %f පේළිය print "Fahrenheit %f" %f ලෙස වෙනස් කිරීම
5. print "Fahrenheit %d" %f පේළිය print "Fahrenheit %f" ලෙස වෙනස් කිරීම
============Theory================
# is a comment
# the calculation gives a floating point data type
>>> k = "user"
>>> v = "niranjan"
>>> "%s=%s" % (k, v)
'user=niranjan'
The whole expression evaluates to a string. The first %s is replaced by the value of k; the second %s is replaced by the value of v. All other characters in the string stay as they are
>>> "Name: %s, age: %d" % ('John', 35)
'Name: John, age: 35'
C style string formatting:
"%d:%d:d" % (hours, minutes, seconds)
>>> print "Today's stock price: %f" % 50.4625
50.462500
>>> print "Today's stock price: %.2f" % 50.4625
50.46
>>> print "Change since yesterday: %+.2f" % 1.5
+1.50
c=input ('Enter Temperature in Celsius:')
f=c*9/5.0+32
print "Fahrenheit %d" %f
දී ඇති ක්රමලේඛය දෝෂ සහිත ය. අපේක්ෂිත ප්රතිදානය ලබා ගැනීම සඳහා එය නිවැරදි විය යුත්තේ පහත සඳහන් කුමන ආකාරයට ද ?
1. #program to convert Celsius Temperature to Fahrenheit යන පේළිය ඉවත් කිරීම
2. c= input('Enter Temperature in Celsius:') පේළිය cinput('Enter Temperature in Celsius.') ලෙස වෙනස් කිරීම
3. F=c*9/5.0+32 පේළිය f=c*9.0/5.0+32 ලෙස වෙනස් කිරීම
4. print "Fahrenheit %d" %f පේළිය print "Fahrenheit %f" %f ලෙස වෙනස් කිරීම
5. print "Fahrenheit %d" %f පේළිය print "Fahrenheit %f" ලෙස වෙනස් කිරීම
============Theory================
# is a comment
# the calculation gives a floating point data type
>>> k = "user"
>>> v = "niranjan"
>>> "%s=%s" % (k, v)
'user=niranjan'
The whole expression evaluates to a string. The first %s is replaced by the value of k; the second %s is replaced by the value of v. All other characters in the string stay as they are
>>> "Name: %s, age: %d" % ('John', 35)
'Name: John, age: 35'
C style string formatting:
"%d:%d:d" % (hours, minutes, seconds)
>>> print "Today's stock price: %f" % 50.4625
50.462500
>>> print "Today's stock price: %.2f" % 50.4625
50.46
>>> print "Change since yesterday: %+.2f" % 1.5
+1.50
Quick Guide to Python List Operations
mylist=[]
x=20
mylist.append(x)
# Add an item to the end of the list;
mylist.insert(i, x)
# insert at i , i should exsit
list.exytend(L)
# Extend the list by appending all the items in the given list
mylist.insert(len(a), x) is equivalent to a.append(x).
mylist.remove(x)
Remove the first item from the list whose value is x.
mylist.pop([i])
Remove the item at the given position in the list, and return it.
Mylist.pop()
# removes and returns the last item in the list.
mylist.index(x)
# Return the index in the list of the first item whose value is x.
mylist.sort()
# Sort the items of the list, in place.
mylist.reverse()
# Reverse the elements of the list, in place.
>>> a = [66.25, 333, 333, 1, 1234.5]
>>> print a.count(333), a.count(66.25), a.count('x')
2 1 0
>>> a.insert(2, 1)
>>> a.append(333)
>>> a
[66.25, 333, 1, 333, 1, 1234.5, 333]
>>> a.index(333)
1
>>> a.remove(333)
>>> a
[66.25, 1, 333, 1, 1234.5, 333]
>>> a.reverse()
>>> a
[333, 1234.5, 1, 333, 1, 66.25]
>>> a.sort()
>>> a
[1, 1, 66.25, 333, 333, 1234.5]
============ADVANCED ==============
x=20
mylist.append(x)
# Add an item to the end of the list;
mylist.insert(i, x)
# insert at i , i should exsit
list.exytend(L)
# Extend the list by appending all the items in the given list
mylist.insert(len(a), x) is equivalent to a.append(x).
mylist.remove(x)
Remove the first item from the list whose value is x.
mylist.pop([i])
Remove the item at the given position in the list, and return it.
Mylist.pop()
# removes and returns the last item in the list.
mylist.index(x)
# Return the index in the list of the first item whose value is x.
mylist.sort()
# Sort the items of the list, in place.
mylist.reverse()
# Reverse the elements of the list, in place.
>>> a = [66.25, 333, 333, 1, 1234.5]
>>> print a.count(333), a.count(66.25), a.count('x')
2 1 0
>>> a.insert(2, 1)
>>> a.append(333)
>>> a
[66.25, 333, 1, 333, 1, 1234.5, 333]
>>> a.index(333)
1
>>> a.remove(333)
>>> a
[66.25, 1, 333, 1, 1234.5, 333]
>>> a.reverse()
>>> a
[333, 1234.5, 1, 333, 1, 66.25]
>>> a.sort()
>>> a
[1, 1, 66.25, 333, 333, 1234.5]
============ADVANCED ==============
Using Lists as Stacks
The list methods make it very easy to use a list as a stack, where the last element added is the first element retrieved (“lastin, firstout”). To add an item to the top of the stack, use append(). To retrieve an item from the top of the stack, use pop() without an explicit index. For example:>>> stack = [3, 4, 5]
>>> stack.append(6)
>>> stack.append(7)
>>> stack
[3, 4, 5, 6, 7]
>>> stack.pop()
7
>>> stack
[3, 4, 5, 6]
>>> stack.pop()
6
>>> stack.pop()
5
>>> stack
[3, 4]
Using Lists as Queues
It is also possible to use a list as a queue, where the first element added is the first element retrieved (“firstin, firstout”); however, lists are not efficient for this purpose. While appends and pops from the end of list are fast, doing inserts or pops from the beginning of a list is slow (because all of the other elements have to be shifted by one).Python File Names  පයිතන ලිපිගොනු නාමය
පහත දැක්වෙන්නේ උෂ්ණත්වය සෙල්සියස් පරිමාණයේ සිට ෆැරන්හයිට් පරිමාණයට පරිවර්ථනය කිරීම සඳහා සැකසූ ක්රමලේඛයකි. ඒ ඇසුරින් අංක 1 හා 2 ප්රශ්නවලට පිළිතුරු සපයන්න.
මෙම පයිතන් ක්රමලේඛය සුරැකීමට (Save) භාවිතා කළ හැකි වඩාත් උචිත සහිත ලිපිගොනු නාමය වන්නේ පහත දැක්වෙන ඒවා අතුරින් කුමක් ද?
1. Temperature Celsius into Fahrenheit.python
2. Temperature Celsius into Fahrenheit.pyp
3. cel_into_fah.pyc
4. cel_into_fah.py
5. temp_conv.pyc
Hints
Python don't use python and pyp extensions
Temperature is a common word for Celsius, Fahrenheit as well as Kelvin
A module is a file containing Python definitions and statements.
The file name is the module name with the suffix .py appended.
hello.pyc is a compiled version of hello.py to speedup of the startup time for short programs.
a “bytecompiled” version of the module spam.
Packages structure Python namespace by using “dotted module names”.
See Below Advanced...
Modules (program.py)
short,
all_lowercase names,
_underscores can be used
Python packages
_underscores is discouraged.
inside
case_senitivity
joined_lower : functions, methods, attributes
joined_lower or ALL_CAPS : constants
StudlyCaps : classes
Attributes: interface, _internal, __private
avoid __python_internal_form_
====================Advanced ===============
Package Sound
#program to convert Celsius Temperature to Fahrenheit
c=input ('Enter Temperature in Celsius:')
f=c*9/5.0+32
print "Fahrenheit %d" %f
මෙම පයිතන් ක්රමලේඛය සුරැකීමට (Save) භාවිතා කළ හැකි වඩාත් උචිත සහිත ලිපිගොනු නාමය වන්නේ පහත දැක්වෙන ඒවා අතුරින් කුමක් ද?
1. Temperature Celsius into Fahrenheit.python
2. Temperature Celsius into Fahrenheit.pyp
3. cel_into_fah.pyc
4. cel_into_fah.py
5. temp_conv.pyc
Hints
Python don't use python and pyp extensions
Temperature is a common word for Celsius, Fahrenheit as well as Kelvin
A module is a file containing Python definitions and statements.
The file name is the module name with the suffix .py appended.
hello.pyc is a compiled version of hello.py to speedup of the startup time for short programs.
a “bytecompiled” version of the module spam.
Packages structure Python namespace by using “dotted module names”.
See Below Advanced...
Naming ▽
file_name.py
Inside code
ClassName, method_name, ExceptionName, function_name, GLOBAL_VAR_NAME, instance_var_name, function_parameter_name, local_var_name.
Modules (program.py)
short,
all_lowercase names,
_underscores can be used
Python packages
_underscores is discouraged.
inside
case_senitivity
joined_lower : functions, methods, attributes
joined_lower or ALL_CAPS : constants
StudlyCaps : classes
Attributes: interface, _internal, __private
avoid __python_internal_form_
====================Advanced ===============
Package Sound
sound/ Toplevel package __init__.py Initialize the sound package formats/ Subpackage for file format conversions __init__.py wavread.py wavwrite.py aiffread.py aiffwrite.py auread.py auwrite.py ... effects/ Subpackage for sound effects __init__.py echo.py surround.py reverse.py ... filters/ Subpackage for filters __init__.py equalizer.py vocoder.py karaoke.py ...
import sound.effects.echo
sound.effects.echo.echofilter(input, output, delay=0.7, atten=4)
sound.effects.echo.echofilter(input, output, delay=0.7, atten=4)
Python Data Types  පයිතන් දත්ත වර්ග
පහත සඳහන් පයිතන් දත්ත වර්ග සලකන්න
එම දත්තඅයත් වන පයිතන් දත්ත අනුපිළිවෙළින්
'win', ['Nimal',55,'male'], ('abc',45,'xyz'), {2:'name','tel':'0721475454'}
1. string, float, double, array
2. string, tuple, dictionary, list
3. string, long, float, complex
4. string, array, integer, list
5. string, list, tuple, dictionary
එම දත්ත
'win', ['Nimal',55,'male'], ('abc',45,'xyz'), {2:'name','tel':'0721475454'}
1. string, float, double, array
2. string, tuple, dictionary, list
3. string, long, float, complex
4. string, array, integer, list
5. string, list, tuple, dictionary
Data type  Description and examples  Bits 
integer  signed integer, +/  2147483647  32 
float  double precision, like 1.23 or 7.8e28  64 
long integer  large integer, trailing L, 234187626348292917L, 7L  
octal integer  base8 integer, leading 0 as in 0177  32 
hexadecimal integer  base16 integer, leading 0x as in 0x9FC  32 
complex  real and imaginary parts written as 3 + 4j or 1.23  0.0073j  
string  ordered collection of characters, enclosed by pairs of ', or " characters  
list  ordered collection of objects, like [1,22,[321,'cow'],'horse']  
dictionary  collection of associated key:data pairs {'first':'alpha','last':'omega'}  
tuples  ('hen','duck',('rabbit','hare'),'dog','cat')  
file  file in disk 
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