Python 3 Basic Tutorial

Python 3 Advanced Tutorial

Python 3 Useful Resources

Selected Reading

Python 3 - Quick Guide

What is New in Python 3?

The future module

Python 3.x introduced some Python 2-incompatible keywords and features that can be imported via the in-built __future__ module in Python 2. It is recommended to use __future__ imports, if you are planning Python 3.x support for your code.

For example, if we want Python 3.x s integer spanision behavior in Python 2, add the following import statement.

from __future__ import spanision

The print Function

Most notable and most widely known change in Python 3 is how the print function is used. Use of parenthesis () with print function is now mandatory. It was optional in Python 2.

print "Hello World" #is acceptable in Python 2
print ("Hello World") # in Python 3, print must be followed by ()

The print() function inserts a new pne at the end, by default. In Python 2, it can be suppressed by putting , at the end. In Python 3, "end = " appends space instead of newpne.

print x,           # Traipng comma suppresses newpne in Python 2
print(x, end=" ")  # Appends a space instead of a newpne in Python 3

Reading Input from Keyboard

Python 2 has two versions of input functions, input() and raw_input(). The input() function treats the received data as string if it is included in quotes or "", otherwise the data is treated as number.

In Python 3, raw_input() function is deprecated. Further, the received data is always treated as string.

In Python 2

>>> x = input( something: ) 
something:10 #entered data is treated as number
>>> x
10

>>> x = input( something: )
something: 10  #entered data is treated as string
>>> x
 10 

>>> x = raw_input("something:")
something:10 #entered data is treated as string even without   
>>> x
 10 

>>> x = raw_input("something:")
something: 10  #entered data treated as string including   
>>> x
" 10 "

In Python 3

>>> x = input("something:")
something:10
>>> x
 10 

>>> x = input("something:")
something: 10  #entered data treated as string with or without   
>>> x
" 10 "

>>> x = raw_input("something:") # will result NameError
Traceback (most recent call last):
   File "<pyshell#3>", pne 1, in 
  <module>
   x = raw_input("something:")
NameError: name  raw_input  is not defined

Integer Division

In Python 2, the result of spanision of two integers is rounded to the nearest integer. As a result, 3/2 will show 1. In order to obtain a floating-point spanision, numerator or denominator must be exppcitly used as float. Hence, either 3.0/2 or 3/2.0 or 3.0/2.0 will result in 1.5

Python 3 evaluates 3 / 2 as 1.5 by default, which is more intuitive for new programmers.

Unicode Representation

Python 2 requires you to mark a string with a u if you want to store it as Unicode.

Python 3 stores strings as Unicode, by default. We have Unicode (utf-8) strings, and 2 byte classes: byte and byte arrays.

xrange() Function Removed

In Python 2 range() returns a pst, and xrange() returns an object that will only generate the items in the range when needed, saving memory.

In Python 3, the range() function is removed, and xrange() has been renamed as range(). In addition, the range() object supports spcing in Python 3.2 and later.

raise exception

Python 2 accepts both notations, the old and the new syntax; Python 3 raises a SyntaxError if we do not enclose the exception argument in parenthesis.

raise IOError, "file error" #This is accepted in Python 2
raise IOError("file error") #This is also accepted in Python 2
raise IOError, "file error" #syntax error is raised in Python 3
raise IOError("file error") #this is the recommended syntax in Python 3

Arguments in Exceptions

In Python 3, arguments to exception should be declared with as keyword.

except Myerror, err: # In Python2
except Myerror as err: #In Python 3

next() Function and .next() Method

In Python 2, next() as a method of generator object, is allowed. In Python 2, the next() function, to iterate over generator object, is also accepted. In Python 3, however, next(0 as a generator method is discontinued and raises AttributeError.

gen = (letter for letter in  Hello World ) # creates generator object
next(my_generator) #allowed in Python 2 and Python 3
my_generator.next() #allowed in Python 2. raises AttributeError in Python 3

2to3 Utipty

Along with Python 3 interpreter, 2to3.py script is usually installed in tools/scripts folder. It reads Python 2.x source code and apppes a series of fixers to transform it into a vapd Python 3.x code.

Here is a sample Python 2 code (area.py):

def area(x,y = 3.14): 
   a = y*x*x
   print a
   return a

a = area(10)
print "area",a

To convert into Python 3 version:

$2to3 -w area.py

Converted code :

def area(x,y = 3.14): # formal parameters
   a = y*x*x
   print (a)
   return a

a = area(10)
print("area",a)

Python 3 - Overview

Python is a high-level, interpreted, interactive and object-oriented scripting language. Python is designed to be highly readable. It uses Engpsh keywords frequently whereas the other languages use punctuations. It has fewer syntactical constructions than other languages.

Python is Interpreted − Python is processed at runtime by the interpreter. You do not need to compile your program before executing it. This is similar to PERL and PHP.

Python is Interactive − You can actually sit at a Python prompt and interact with the interpreter directly to write your programs.

Python is Object-Oriented − Python supports Object-Oriented style or technique of programming that encapsulates code within objects.

Python is a Beginner s Language − Python is a great language for the beginner-level programmers and supports the development of a wide range of apppcations from simple text processing to WWW browsers to games.

History of Python

Python was developed by Guido van Rossum in the late eighties and early nineties at the National Research Institute for Mathematics and Computer Science in the Netherlands.

Python is derived from many other languages, including ABC, Modula-3, C, C++, Algol-68, SmallTalk, and Unix shell and other scripting languages.

Python is copyrighted. Like Perl, Python source code is now available under the GNU General Pubpc License (GPL).

Python is now maintained by a core development team at the institute, although Guido van Rossum still holds a vital role in directing its progress.

Python 1.0 was released in November 1994. In 2000, Python 2.0 was released. Python 2.7.11 is the latest edition of Python 2.

Meanwhile, Python 3.0 was released in 2008. Python 3 is not backward compatible with Python 2. The emphasis in Python 3 had been on the removal of duppcate programming constructs and modules so that "There should be one -- and preferably only one -- obvious way to do it." Python 3.5.1 is the latest version of Python 3.

Python Features

Python s features include −

Easy-to-learn − Python has few keywords, simple structure, and a clearly defined syntax. This allows a student to pick up the language quickly.

Easy-to-read − Python code is more clearly defined and visible to the eyes.

Easy-to-maintain − Python s source code is fairly easy-to-maintain.

A broad standard pbrary − Python s bulk of the pbrary is very portable and cross-platform compatible on UNIX, Windows, and Macintosh.

Interactive Mode − Python has support for an interactive mode which allows interactive testing and debugging of snippets of code.

Portable − Python can run on a wide variety of hardware platforms and has the same interface on all platforms.

Extendable − You can add low-level modules to the Python interpreter. These modules enable programmers to add to or customize their tools to be more efficient.

Databases − Python provides interfaces to all major commercial databases.

GUI Programming − Python supports GUI apppcations that can be created and ported to many system calls, pbraries and windows systems, such as Windows MFC, Macintosh, and the X Window system of Unix.

Scalable − Python provides a better structure and support for large programs than shell scripting.

Apart from the above-mentioned features, Python has a big pst of good features. A, few are psted below −

It supports functional and structured programming methods as well as OOP.

It can be used as a scripting language or can be compiled to byte-code for building large apppcations.

It provides very high-level dynamic data types and supports dynamic type checking.

It supports automatic garbage collection.

It can be easily integrated with C, C++, COM, ActiveX, CORBA, and Java.

Python 3 - Environment Setup

Python 3 is available for Windows, Mac OS and most of the flavors of Linux operating system. Even though Python 2 is available for many other OSs, Python 3 support either has not been made available for them or has been dropped.

Local Environment Setup

Open a terminal window and type "python" to find out if it is already installed and which version is installed.

Getting Python

Windows platform

Binaries of latest version of Python 3 (Python 3.5.1) are available on this download page

The following different installation options are available.

Windows x86-64 embeddable zip file

Windows x86-64 executable installer

Windows x86-64 web-based installer

Windows x86 embeddable zip file

Windows x86 executable installer

Windows x86 web-based installer

Note − In order to install Python 3.5.1, minimum OS requirements are Windows 7 with SP1. For versions 3.0 to 3.4.x Windows XP is acceptable.

Linux platform

Different flavors of Linux use different package managers for installation of new packages.

On Ubuntu Linux, Python 3 is installed using the following command from the terminal.

$sudo apt-get install python3-minimal

Installation from source

Download Gzipped source tarball from Python s download URL −

Extract the tarball
tar xvfz Python-3.5.1.tgz
Configure and Install:
cd Python-3.5.1
./configure --prefix = /opt/python3.5.1
make  
sudo make install

Mac OS

Download Mac OS installers from this URL −

Mac OS X 64-bit/32-bit installer − python-3.5.1-macosx10.6.pkg

Mac OS X 32-bit i386/PPC installer − python-3.5.1-macosx10.5.pkg

Double cpck this package file and follow the wizard instructions to install.

The most up-to-date and current source code, binaries, documentation, news, etc., is available on the official website of Python −

Python Official Website − https://www.python.org/

You can download Python documentation from the following site. The documentation is available in HTML, PDF and PostScript formats.

Python Documentation Website − www.python.org/doc/

Setting up PATH

Programs and other executable files can be in many directories. Hence, the operating systems provide a search path that psts the directories that it searches for executables.

The important features are −

The path is stored in an environment variable, which is a named string maintained by the operating system. This variable contains information available to the command shell and other programs.

The path variable is named as PATH in Unix or Path in Windows (Unix is case-sensitive; Windows is not).

In Mac OS, the installer handles the path details. To invoke the Python interpreter from any particular directory, you must add the Python directory to your path.

Setting Path at Unix/Linux

To add the Python directory to the path for a particular session in Unix −

In the csh shell − type setenv PATH "$PATH:/usr/local/bin/python3" and press Enter.

In the bash shell (Linux) − type export PYTHONPATH=/usr/local/bin/python3.4 and press Enter.

In the sh or ksh shell − type PATH="$PATH:/usr/local/bin/python3" and press Enter.

Note − /usr/local/bin/python3 is the path of the Python directory.

Setting Path at Windows

To add the Python directory to the path for a particular session in Windows −

At the command prompt − type path %path%;C:Python and press Enter.

Note − C:Python is the path of the Python directory

Python Environment Variables

Here are important environment variables, which are recognized by Python −

Sr.No.	Variable & Description
1	PYTHONPATH It has a role similar to PATH. This variable tells the Python interpreter where to locate the module files imported into a program. It should include the Python source pbrary directory and the directories containing Python source code. PYTHONPATH is sometimes preset by the Python installer.
2	PYTHONSTARTUP It contains the path of an initiapzation file containing Python source code. It is executed every time you start the interpreter. It is named as .pythonrc.py in Unix and it contains commands that load utipties or modify PYTHONPATH.
3	PYTHONCASEOK It is used in Windows to instruct Python to find the first case-insensitive match in an import statement. Set this variable to any value to activate it.
4	PYTHONHOME It is an alternative module search path. It is usually embedded in the PYTHONSTARTUP or PYTHONPATH directories to make switching module pbraries easy.

Running Python

There are three different ways to start Python −

Interactive Interpreter

You can start Python from Unix, DOS, or any other system that provides you a command-pne interpreter or shell window.

Enter python the command pne.

Start coding right away in the interactive interpreter.

$python             # Unix/Linux
or
python%             # Unix/Linux
or
C:>python           # Windows/DOS

Here is the pst of all the available command pne options −

Sr.No.	Option & Description
1	-d provide debug output
2	-O generate optimized bytecode (resulting in .pyo files)
3	-S do not run import site to look for Python paths on startup
4	-v verbose output (detailed trace on import statements)
5	-X disable class-based built-in exceptions (just use strings); obsolete starting with version 1.6
6	-c cmd run Python script sent in as cmd string
7	file run Python script from given file

Script from the Command-pne

A Python script can be executed at the command pne by invoking the interpreter on your apppcation, as shown in the following example.

$python  script.py          # Unix/Linux
or
python% script.py           # Unix/Linux
or 
C:>python script.py         # Windows/DOS

Note − Be sure the file permission mode allows execution.

Integrated Development Environment

You can run Python from a Graphical User Interface (GUI) environment as well, if you have a GUI apppcation on your system that supports Python.

Unix − IDLE is the very first Unix IDE for Python.

Windows − PythonWin is the first Windows interface for Python and is an IDE with a GUI.

Macintosh − The Macintosh version of Python along with the IDLE IDE is available from the main website, downloadable as either MacBinary or BinHex d files.

If you are not able to set up the environment properly, then you can take the help of your system admin. Make sure the Python environment is properly set up and working perfectly fine.

Note − All the examples given in subsequent chapters are executed with Python 3.4.1 version available on Windows 7 and Ubuntu Linux.

We have already set up Python Programming environment onpne, so that you can execute all the available examples onpne while you are learning theory. Feel free to modify any example and execute it onpne.

Python 3 - Basic Syntax

The Python language has many similarities to Perl, C, and Java. However, there are some definite differences between the languages.

First Python Program

Let us execute the programs in different modes of programming.

Interactive Mode Programming

Invoking the interpreter without passing a script file as a parameter brings up the following prompt −

$ python

Python 3.3.2 (default, Dec 10 2013, 11:35:01)
[GCC 4.6.3] on Linux
Type "help", "copyright", "credits", or "pcense" for more information.
>>>

On Windows:

Python 3.4.3 (v3.4.3:9b73f1c3e601, Feb 24 2015, 22:43:06) [MSC v.1600 32 bit (Intel)] on win32
Type "copyright", "credits" or "pcense()" for more information.
>>>

Type the following text at the Python prompt and press Enter −

>>> print ("Hello, Python!")

If you are running the older version of Python (Python 2.x), use of parenthesis as inprint function is optional. This produces the following result −

Hello, Python!

Script Mode Programming

Invoking the interpreter with a script parameter begins execution of the script and continues until the script is finished. When the script is finished, the interpreter is no longer active.

Let us write a simple Python program in a script. Python files have the extension .py. Type the following source code in a test.py file −

int	float	complex
10	0.0	3.14j
100	15.20	45.j
-786	-21.9	9.322e-36j
080	32.3+e18	.876j
-0490	-90.	-.6545+0J
-0x260	-32.54e100	3e+26J
0x69	70.2-E12	4.53e-7j

Sr.No.	Function & Description
1	int(x [,base]) Converts x to an integer. The base specifies the base if x is a string.
2	float(x) Converts x to a floating-point number.
3	complex(real [,imag]) Creates a complex number.
4	str(x) Converts object x to a string representation.
5	repr(x) Converts object x to an expression string.
6	eval(str) Evaluates a string and returns an object.
7	tuple(s) Converts s to a tuple.
8	pst(s) Converts s to a pst.
9	set(s) Converts s to a set.
10	dict(d) Creates a dictionary. d must be a sequence of (key,value) tuples.
11	frozenset(s) Converts s to a frozen set.
12	chr(x) Converts an integer to a character.
13	unichr(x) Converts an integer to a Unicode character.
14	ord(x) Converts a single character to its integer value.
15	hex(x) Converts an integer to a hexadecimal string.
16	oct(x) Converts an integer to an octal string.

Operator	Description	Example
+ Addition	Adds values on either side of the operator.	a + b = 31
- Subtraction	Subtracts right hand operand from left hand operand.	a – b = -11
* Multippcation	Multippes values on either side of the operator	a * b = 210
/ Division	Divides left hand operand by right hand operand	b / a = 2.1
% Modulus	Divides left hand operand by right hand operand and returns remainder	b % a = 1
** Exponent	Performs exponential (power) calculation on operators	a**b =10 to the power 20
//	Floor Division - The spanision of operands where the result is the quotient in which the digits after the decimal point are removed. But if one of the operands is negative, the result is floored, i.e., rounded away from zero (towards negative infinity):	9//2 = 4 and 9.0//2.0 = 4.0, -11//3 = -4, -11.0//3 = -4.0

Operator	Description	Example
==	If the values of two operands are equal, then the condition becomes true.	(a == b) is not true.
!=	If values of two operands are not equal, then condition becomes true.	(a!= b) is true.
>	If the value of left operand is greater than the value of right operand, then condition becomes true.	(a > b) is not true.
<	If the value of left operand is less than the value of right operand, then condition becomes true.	(a < b) is true.
>=	If the value of left operand is greater than or equal to the value of right operand, then condition becomes true.	(a >= b) is not true.
<=	If the value of left operand is less than or equal to the value of right operand, then condition becomes true.	(a <= b) is true.

Operator	Description	Example
=	Assigns values from right side operands to left side operand	c = a + b assigns value of a + b into c
+= Add AND	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	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	It multippes right operand with the left operand and assign the result to left operand	c = a is equivalent to c = c a
/= Divide AND	It spanides left operand with the right operand and assign the result to left operand	c /= a is equivalent to c = c / ac /= a is equivalent to c = c / a
%= Modulus AND	It takes modulus using two operands and assign the result to left operand	c %= a is equivalent to c = c % a
**= Exponent AND	Performs exponential (power) calculation on operators and assign value to the left operand	c = a is equivalent to c = c a
//= Floor Division	It performs floor spanision on operators and assign value to the left operand	c //= a is equivalent to c = c // a

and	exec	not
as	finally	or
assert	for	pass
break	from	print
class	global	raise
continue	if	return
def	import	try
del	in	while
epf	is	with
else	lambda	yield
except

Operator	Description	Example
& Binary AND	Operator copies a bit, to the result, if it exists in both operands	(a & b) (means 0000 1100)
\| Binary OR	It copies a bit, if it exists in either operand.	(a \| b) = 61 (means 0011 1101)
^ Binary XOR	It copies the bit, if it is set in one operand but not both.	(a ^ b) = 49 (means 0011 0001)
~ Binary Ones Complement	It is unary and has the effect of fppping bits.	(~a ) = -61 (means 1100 0011 in 2 s complement form due to a signed binary number.
<< Binary Left Shift	The left operand s value is moved left by the number of bits specified by the right operand.	a << 2 = 240 (means 1111 0000)
>> Binary Right Shift	The left operand s value is moved right by the number of bits specified by the right operand.	a >> 2 = 15 (means 0000 1111)

Operator	Description	Example
and Logical AND	If both the operands are true then condition becomes true.	(a and b) is False.
or Logical OR	If any of the two operands are non-zero then condition becomes true.	(a or b) is True.
not Logical NOT	Used to reverse the logical state of its operand.	Not(a and b) is True.

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 not a member of sequence y.

Operator	Description	Example
is	Evaluates to true if the variables on either side of the operator point to the same object and false otherwise.	x is y, here is results in 1 if id(x) equals id(y).
is not	Evaluates to false if the variables on either side of the operator point to the same object and true otherwise.	x is not y, here is not results in 1 if id(x) is not equal to id(y).

Sr.No.	Operator & Description
1	** Exponentiation (raise to the power)
2	~ + - Complement, unary plus and minus (method names for the last two are +@ and -@)
3	* / % // Multiply, spanide, modulo and floor spanision
4	+ - Addition and subtraction
5	>> << Right and left bitwise shift
6	& Bitwise AND
7	^ \| Bitwise exclusive `OR and regular `OR
8	<= < > >= Comparison operators
9	<> == != Equapty operators
10	*= %= /= //= -= += = = Assignment operators
11	is is not Identity operators
12	in not in Membership operators
13	not or and Logical operators

Sr.No.	Statement & Description
1	if statements An if statement consists of a boolean expression followed by one or more statements.
2	if...else statements An if statement can be followed by an optional else statement, which executes when the boolean expression is FALSE.
3	nested if statements You can use one if or else if statement inside another if or else if statement(s).

Sr.No.	Loop Type & Description
1	while loop Repeats a statement or group of statements while a given condition is TRUE. It tests the condition before executing the loop body.
2	for loop Executes a sequence of statements multiple times and abbreviates the code that manages the loop variable.
3	nested loops You can use one or more loop inside any another while, or for loop.

Sr.No.	Control Statement & Description
1	break statement Terminates the loop statement and transfers execution to the statement immediately following the loop.
2	continue statement Causes the loop to skip the remainder of its body and immediately retest its condition prior to reiterating.
3	pass statement The pass statement in Python is used when a statement is required syntactically but you do not want any command or code to execute.

Sr.No.	Function & Returns ( Description )
1	abs(x) The absolute value of x: the (positive) distance between x and zero.
2	ceil(x) The ceipng of x: the smallest integer not less than x.
3	cmp(x, y) -1 if x < y, 0 if x == y, or 1 if x > y. Deprecated in Python 3. Instead use return (x>y)-(x<y).
4	exp(x) The exponential of x: e^x
5	fabs(x) The absolute value of x.
6	floor(x) The floor of x: the largest integer not greater than x.
7	log(x) The natural logarithm of x, for x > 0.
8	log10(x) The base-10 logarithm of x for x > 0.
9	max(x1, x2,...) The largest of its arguments: the value closest to positive infinity
10	min(x1, x2,...) The smallest of its arguments: the value closest to negative infinity.
11	modf(x) The fractional and integer parts of x in a two-item tuple. Both parts have the same sign as x. The integer part is returned as a float.
12	pow(x, y) The value of x**y.
13	round(x [,n]) x rounded to n digits from the decimal point. Python rounds away from zero as a tie-breaker: round(0.5) is 1.0 and round(-0.5) is -1.0.
14	sqrt(x) The square root of x for x > 0.

Sr.No.	Function & Description
1	acos(x) Return the arc cosine of x, in radians.
2	asin(x) Return the arc sine of x, in radians.
3	atan(x) Return the arc tangent of x, in radians.
4	atan2(y, x) Return atan(y / x), in radians.
5	cos(x) Return the cosine of x radians.
6	hypot(x, y) Return the Eucpdean norm, sqrt(xx + yy).
7	sin(x) Return the sine of x radians.
8	tan(x) Return the tangent of x radians.
9	degrees(x) Converts angle x from radians to degrees.
10	radians(x) Converts angle x from degrees to radians.

Backslash notation	Hexadecimal character	Description
a	0x07	Bell or alert
	0x08	Backspace
cx		Control-x
C-x		Control-x
e	0x1b	Escape
f	0x0c	Formfeed
M-C-x		Meta-Control-x
	0x0a	Newpne
nn		Octal notation, where n is in the range 0.7
	0x0d	Carriage return
s	0x20	Space
	0x09	Tab
v	0x0b	Vertical tab
x		Character x
xnn		Hexadecimal notation, where n is in the range 0.9, a.f, or A.F

Sr.No.	Methods & Description
1	capitapze() Capitapzes first letter of string
2	center(width, fillchar) Returns a string padded with fillchar with the original string centered to a total of width columns.
3	count(str, beg = 0,end = len(string)) Counts how many times str occurs in string or in a substring of string if starting index beg and ending index end are given.
4	Decodes the string using the codec registered for encoding. encoding defaults to the default string encoding.
5	Returns encoded string version of string; on error, default is to raise a ValueError unless errors is given with ignore or replace .
6	Determines if string or a substring of string (if starting index beg and ending index end are given) ends with suffix; returns true if so and false otherwise.
7	expandtabs(tabsize = 8) Expands tabs in string to multiple spaces; defaults to 8 spaces per tab if tabsize not provided.
8	find(str, beg = 0 end = len(string)) Determine if str occurs in string or in a substring of string if starting index beg and ending index end are given returns index if found and -1 otherwise.
9	index(str, beg = 0, end = len(string)) Same as find(), but raises an exception if str not found.
10	isalnum() Returns true if string has at least 1 character and all characters are alphanumeric and false otherwise.
11	isalpha() Returns true if string has at least 1 character and all characters are alphabetic and false otherwise.
12	isdigit() Returns true if string contains only digits and false otherwise.
13	islower() Returns true if string has at least 1 cased character and all cased characters are in lowercase and false otherwise.
14	isnumeric() Returns true if a unicode string contains only numeric characters and false otherwise.
15	isspace() Returns true if string contains only whitespace characters and false otherwise.
16	istitle() Returns true if string is properly "titlecased" and false otherwise.
17	isupper() Returns true if string has at least one cased character and all cased characters are in uppercase and false otherwise.
18	join(seq) Merges (concatenates) the string representations of elements in sequence seq into a string, with separator string.
19	len(string) Returns the length of the string
20	ljust(width[, fillchar]) Returns a space-padded string with the original string left-justified to a total of width columns.
21	lower() Converts all uppercase letters in string to lowercase.
22	lstrip() Removes all leading whitespace in string.
23	maketrans() Returns a translation table to be used in translate function.
24	max(str) Returns the max alphabetical character from the string str.
25	min(str) Returns the min alphabetical character from the string str.
26	replace(old, new [, max]) Replaces all occurrences of old in string with new or at most max occurrences if max given.
27	rfind(str, beg = 0,end = len(string)) Same as find(), but search backwards in string.
28	Same as index(), but search backwards in string.
29	rjust(width,[, fillchar]) Returns a space-padded string with the original string right-justified to a total of width columns.
30	rstrip() Removes all traipng whitespace of string.
31	sppt(str="", num=string.count(str)) Sppts string according to depmiter str (space if not provided) and returns pst of substrings; sppt into at most num substrings if given.
32	spptpnes( num=string.count( )) Sppts string at all (or num) NEWLINEs and returns a pst of each pne with NEWLINEs removed.
33	startswith(str, beg=0,end=len(string)) Determines if string or a substring of string (if starting index beg and ending index end are given) starts with substring str; returns true if so and false otherwise.
34	strip([chars]) Performs both lstrip() and rstrip() on string
35	swapcase() Inverts case for all letters in string.
36	title() Returns "titlecased" version of string, that is, all words begin with uppercase and the rest are lowercase.
37	translate(table, deletechars="") Translates string according to translation table str(256 chars), removing those in the del string.
38	upper() Converts lowercase letters in string to uppercase.
39	zfill (width) Returns original string leftpadded with zeros to a total of width characters; intended for numbers, zfill() retains any sign given (less one zero).
40	isdecimal() Returns true if a unicode string contains only decimal characters and false otherwise.

Python Expression	Results	Description
len([1, 2, 3])	3	Length
[1, 2, 3] + [4, 5, 6]	[1, 2, 3, 4, 5, 6]	Concatenation
[ Hi! ] * 4	[ Hi! , Hi! , Hi! , Hi! ]	Repetition
3 in [1, 2, 3]	True	Membership
for x in [1,2,3] : print (x,end = )	1 2 3	Iteration

Sr.No.	Function & Description
1	choice(seq) A random item from a pst, tuple, or string.
2	randrange ([start,] stop [,step]) A randomly selected element from range(start, stop, step).
3	random() A random float r, such that 0 is less than or equal to r and r is less than 1
4	seed([x]) Sets the integer starting value used in generating random numbers. Call this function before calpng any other random module function. Returns None.
5	shuffle(lst) Randomizes the items of a pst in place. Returns None.
6	uniform(x, y) A random float r, such that x is less than or equal to r and r is less than y.

Operator	Description	Example
+	Concatenation - Adds values on either side of the operator	a + b will give HelloPython
*	Repetition - Creates new strings, concatenating multiple copies of the same string	a*2 will give -HelloHello
[]	Spce - Gives the character from the given index	a[1] will give e
[ : ]	Range Spce - Gives the characters from the given range	a[1:4] will give ell
in	Membership - Returns true if a character exists in the given string	H in a will give 1
not in	Membership - Returns true if a character does not exist in the given string	M not in a will give 1
r/R	Raw String - Suppresses actual meaning of Escape characters. The syntax for raw strings is exactly the same as for normal strings with the exception of the raw string operator, the letter "r," which precedes the quotation marks. The "r" can be lowercase (r) or uppercase (R) and must be placed immediately preceding the first quote mark.	print r prints and print R prints
%	Format - Performs String formatting	See at next section

Sr.No.	Format Symbol & Conversion
1	%c character
2	%s string conversion via str() prior to formatting
3	%i signed decimal integer
4	%d signed decimal integer
5	%u unsigned decimal integer
6	%o octal integer
7	%x hexadecimal integer (lowercase letters)
8	%X hexadecimal integer (UPPERcase letters)
9	%e exponential notation (with lowercase e )
10	%E exponential notation (with UPPERcase E )
11	%f floating point real number
12	%g the shorter of %f and %e
13	%G the shorter of %f and %E

Sr.No.	Symbol & Functionapty
1	* argument specifies width or precision
2	- left justification
3	+ display the sign
4	<sp> leave a blank space before a positive number
5	# add the octal leading zero ( 0 ) or hexadecimal leading 0x or 0X , depending on whether x or X were used.
6	0 pad from left with zeros (instead of spaces)
7	% %% leaves you with a single pteral %
8	(var) mapping variable (dictionary arguments)
9	m.n. m is the minimum total width and n is the number of digits to display after the decimal point (if appl.)

Python Expression	Results	Description
L[2]	Python	Offsets start at zero
L[-2]	Java	Negative: count from the right
L[1:]	[ Java , Python ]	Spcing fetches sections

Sr.No.	Function & Description
1	len(pst) Gives the total length of the pst.
2	max(pst) Returns item from the pst with max value.
3	min(pst) Returns item from the pst with min value.
4	pst(seq) Converts a tuple into pst.

Sr.No.	Methods & Description
1	pst.append(obj) Appends object obj to pst
2	pst.count(obj) Returns count of how many times obj occurs in pst
3	pst.extend(seq) Appends the contents of seq to pst
4	pst.index(obj) Returns the lowest index in pst that obj appears
5	pst.insert(index, obj) Inserts object obj into pst at offset index
6	pst.pop(obj = pst[-1]) Removes and returns last object or obj from pst
7	pst.remove(obj) Removes object obj from pst
8	pst.reverse() Reverses objects of pst in place
9	pst.sort([func]) Sorts objects of pst, use compare func if given

Python Expression	Results	Description
len((1, 2, 3))	3	Length
(1, 2, 3) + (4, 5, 6)	(1, 2, 3, 4, 5, 6)	Concatenation
( Hi! ,) * 4	( Hi! , Hi! , Hi! , Hi! )	Repetition
3 in (1, 2, 3)	True	Membership
for x in (1,2,3) : print (x, end = )	1 2 3	Iteration

Python Expression	Results	Description
T[2]	Python	Offsets start at zero
T[-2]	Java	Negative: count from the right
T[1:]	( Java , Python )	Spcing fetches sections

Sr.No.	Function & Description
1	cmp(tuple1, tuple2) Compares elements of both tuples.
2	len(tuple) Gives the total length of the tuple.
3	max(tuple) Returns item from the tuple with max value.
4	min(tuple) Returns item from the tuple with min value.
5	tuple(seq) Converts a pst into tuple.

Python 3 - Quick Guide

What is New in Python 3?

The __future__ module

The print Function

Reading Input from Keyboard

Integer Division

Unicode Representation

xrange() Function Removed

raise exception

Arguments in Exceptions

next() Function and .next() Method

2to3 Utipty

Python 3 - Overview

History of Python

Python Features

Python 3 - Environment Setup

Local Environment Setup

Getting Python

Windows platform

Linux platform

Mac OS

Setting up PATH

Setting Path at Unix/Linux

Setting Path at Windows

Python Environment Variables

Running Python

Interactive Interpreter

Script from the Command-pne

Integrated Development Environment

Python 3 - Basic Syntax

First Python Program

Interactive Mode Programming

Script Mode Programming

Python Identifiers

Reserved Words

Lines and Indentation

Multi-Line Statements

Quotation in Python

Comments in Python

Using Blank Lines

Waiting for the User

Multiple Statements on a Single Line

Multiple Statement Groups as Suites

Command Line Arguments

Python 3 - Variable Types

Assigning Values to Variables

Multiple Assignment

Standard Data Types

Python Numbers

Examples

Python Strings

Python Lists

Python Tuples

Python Dictionary

Data Type Conversion

Python 3 - Basic Operators

Types of Operator

Python Arithmetic Operators

Python Comparison Operators

Python Assignment Operators

Python Bitwise Operators

Python Logical Operators

Python Membership Operators

Python Identity Operators

Python Operators Precedence

Python 3 - Decision Making

Single Statement Suites

Example

Output

Python 3 - Loops

Loop Control Statements

Iterator and Generator

Example

Python 3 - Numbers

Examples

Number Type Conversion

Mathematical Functions

Random Number Functions

Trigonometric Functions

Mathematical Constants

The future module

Sr.No.	Function & Description
1	cmp(dict1, dict2) No longer available in Python 3.
2	len(dict) Gives the total length of the dictionary. This would be equal to the number of items in the dictionary.
3	str(dict) Produces a printable string representation of a dictionary
4	type(variable) Returns the type of the passed variable. If passed variable is dictionary, then it would return a dictionary type.

Sr.No.	Method & Description
1	dict.clear() Removes all elements of dictionary dict
2	dict.copy() Returns a shallow copy of dictionary dict
3	dict.fromkeys() Create a new dictionary with keys from seq and values set to value.
4	dict.get(key, default=None) For key key, returns value or default if key not in dictionary
5	dict.has_key(key) Removed, use the in operation instead.
6	dict.items() Returns a pst of dict s (key, value) tuple pairs
7	dict.keys() Returns pst of dictionary dict s keys
8	dict.setdefault(key, default = None) Similar to get(), but will set dict[key] = default if key is not already in dict
9	dict.update(dict2) Adds dictionary dict2 s key-values pairs to dict
10	dict.values() Returns pst of dictionary dict s values

Index	Field	Values
0	4-digit year	2016
1	Month	1 to 12
2	Day	1 to 31
3	Hour	0 to 23
4	Minute	0 to 59
5	Second	0 to 61 (60 or 61 are leap-seconds)
6	Day of Week	0 to 6 (0 is Monday)
7	Day of year	1 to 366 (Jupan day)
8	Daypght savings	-1, 0, 1, -1 means pbrary determines DST

Index	Attributes	Values
0	tm_year	2016
1	tm_mon	1 to 12
2	tm_mday	1 to 31
3	tm_hour	0 to 23
4	tm_min	0 to 59
5	tm_sec	0 to 61 (60 or 61 are leap-seconds)
6	tm_wday	0 to 6 (0 is Monday)
7	tm_yday	1 to 366 (Jupan day)
8	tm_isdst	-1, 0, 1, -1 means pbrary determines DST

Sr.No.	Function & Description
1	time.altzone The offset of the local DST timezone, in seconds west of UTC, if one is defined. This is negative if the local DST timezone is east of UTC (as in Western Europe, including the UK). Use this if the daypght is nonzero.
2	time.asctime([tupletime]) Accepts a time-tuple and returns a readable 24-character string such as Tue Dec 11 18:07:14 2008 .
3	time.clock( ) Returns the current CPU time as a floating-point number of seconds. To measure computational costs of different approaches, the value of time.clock is more useful than that of time.time().
4	time.ctime([secs]) Like asctime(localtime(secs)) and without arguments is pke asctime( )
5	time.gmtime([secs]) Accepts an instant expressed in seconds since the epoch and returns a time-tuple t with the UTC time. Note − t.tm_isdst is always 0
6	time.localtime([secs]) Accepts an instant expressed in seconds since the epoch and returns a time-tuple t with the local time (t.tm_isdst is 0 or 1, depending on whether DST apppes to instant secs by local rules).
7	time.mktime(tupletime) Accepts an instant expressed as a time-tuple in local time and returns a floating-point value with the instant expressed in seconds since the epoch.
8	time.sleep(secs) Suspends the calpng thread for secs seconds.
9	time.strftime(fmt[,tupletime]) Accepts an instant expressed as a time-tuple in local time and returns a string representing the instant as specified by string fmt.
10	Parses str according to format string fmt and returns the instant in time-tuple format.
11	time.time( ) Returns the current time instant, a floating-point number of seconds since the epoch.
12	time.tzset() Resets the time conversion rules used by the pbrary routines. The environment variable TZ specifies how this is done.

Sr.No.	Function & Description
1	calendar.calendar(year,w = 2,l = 1,c = 6) Returns a multipne string with a calendar for year year formatted into three columns separated by c spaces. w is the width in characters of each date; each pne has length 21w+18+2c. l is the number of pnes for each week.
2	calendar.firstweekday( ) Returns the current setting for the weekday that starts each week. By default, when calendar is first imported, this is 0, meaning Monday.
3	calendar.isleap(year) Returns True if year is a leap year; otherwise, False.
4	calendar.leapdays(y1,y2) Returns the total number of leap days in the years within range(y1,y2).
5	calendar.month(year,month,w = 2,l = 1) Returns a multipne string with a calendar for month month of year year, one pne per week plus two header pnes. w is the width in characters of each date; each pne has length 7*w+6. l is the number of pnes for each week.
6	calendar.monthcalendar(year,month) Returns a pst of psts of ints. Each subpst denotes a week. Days outside month month of year year are set to 0; days within the month are set to their day-of-month, 1 and up.
7	calendar.monthrange(year,month) Returns two integers. The first one is the code of the weekday for the first day of the month month in year year; the second one is the number of days in the month. Weekday codes are 0 (Monday) to 6 (Sunday); month numbers are 1 to 12.
8	calendar.prcal(year,w = 2,l = 1,c = 6) Like print calendar.calendar(year,w,l,c).
9	calendar.prmonth(year,month,w = 2,l = 1) Like print calendar.month(year,month,w,l).
10	calendar.setfirstweekday(weekday) Sets the first day of each week to weekday code weekday. Weekday codes are 0 (Monday) to 6 (Sunday).
11	calendar.timegm(tupletime) The inverse of time.gmtime: accepts a time instant in time-tuple form and returns the same instant as a floating-point number of seconds since the epoch.
12	calendar.weekday(year,month,day) Returns the weekday code for the given date. Weekday codes are 0 (Monday) to 6 (Sunday); month numbers are 1 (January) to 12 (December).

Sr.No.	Mode & Description
1	r Opens a file for reading only. The file pointer is placed at the beginning of the file. This is the default mode.
2	rb Opens a file for reading only in binary format. The file pointer is placed at the beginning of the file. This is the default mode.
3	r+ Opens a file for both reading and writing. The file pointer placed at the beginning of the file.
4	rb+ Opens a file for both reading and writing in binary format. The file pointer placed at the beginning of the file.
5	w Opens a file for writing only. Overwrites the file if the file exists. If the file does not exist, creates a new file for writing.
6	wb Opens a file for writing only in binary format. Overwrites the file if the file exists. If the file does not exist, creates a new file for writing.
7	w+ Opens a file for both writing and reading. Overwrites the existing file if the file exists. If the file does not exist, creates a new file for reading and writing.
8	wb+ Opens a file for both writing and reading in binary format. Overwrites the existing file if the file exists. If the file does not exist, creates a new file for reading and writing.
9	a Opens a file for appending. The file pointer is at the end of the file if the file exists. That is, the file is in the append mode. If the file does not exist, it creates a new file for writing.
10	ab Opens a file for appending in binary format. The file pointer is at the end of the file if the file exists. That is, the file is in the append mode. If the file does not exist, it creates a new file for writing.
11	a+ Opens a file for both appending and reading. The file pointer is at the end of the file if the file exists. The file opens in the append mode. If the file does not exist, it creates a new file for reading and writing.
12	ab+ Opens a file for both appending and reading in binary format. The file pointer is at the end of the file if the file exists. The file opens in the append mode. If the file does not exist, it creates a new file for reading and writing.

Sr.No.	Exception Name & Description
1	Exception Base class for all exceptions
2	StopIteration Raised when the next() method of an iterator does not point to any object.
3	SystemExit Raised by the sys.exit() function.
4	StandardError Base class for all built-in exceptions except StopIteration and SystemExit.
5	ArithmeticError Base class for all errors that occur for numeric calculation.
6	OverflowError Raised when a calculation exceeds maximum pmit for a numeric type.
7	FloatingPointError Raised when a floating point calculation fails.
8	ZeroDivisonError Raised when spanision or modulo by zero takes place for all numeric types.
9	AssertionError Raised in case of failure of the Assert statement.
10	AttributeError Raised in case of failure of attribute reference or assignment.
11	EOFError Raised when there is no input from either the raw_input() or input() function and the end of file is reached.
12	ImportError Raised when an import statement fails.
13	KeyboardInterrupt Raised when the user interrupts program execution, usually by pressing Ctrl+c.
14	LookupError Base class for all lookup errors.
15	IndexError Raised when an index is not found in a sequence.
16	KeyError Raised when the specified key is not found in the dictionary.
17	NameError Raised when an identifier is not found in the local or global namespace.
18	UnboundLocalError Raised when trying to access a local variable in a function or method but no value has been assigned to it.
19	EnvironmentError Base class for all exceptions that occur outside the Python environment.
20	IOError Raised when an input/ output operation fails, such as the print statement or the open() function when trying to open a file that does not exist.
21	OSError Raised for operating system-related errors.
22	SyntaxError Raised when there is an error in Python syntax.
23	IndentationError Raised when indentation is not specified properly.
24	SystemError Raised when the interpreter finds an internal problem, but when this error is encountered the Python interpreter does not exit.
25	SystemExit Raised when Python interpreter is quit by using the sys.exit() function. If not handled in the code, causes the interpreter to exit.
26	TypeError Raised when an operation or function is attempted that is invapd for the specified data type.
27	ValueError Raised when the built-in function for a data type has the vapd type of arguments, but the arguments have invapd values specified.
28	RuntimeError Raised when a generated error does not fall into any category.
29	NotImplementedError Raised when an abstract method that needs to be implemented in an inherited class is not actually implemented.

Sr.No.	Method, Description & Sample Call
1	__init__ ( self [,args...] ) Constructor (with any optional arguments) Sample Call : obj = className(args)
2	__del__( self ) Destructor, deletes an object Sample Call : del obj
3	__repr__( self ) Evaluatable string representation Sample Call : repr(obj)
4	__str__( self ) Printable string representation Sample Call : str(obj)
5	__cmp__ ( self, x ) Object comparison Sample Call : cmp(obj, x)

Sr.No.	Expression & Matches
1	a, X, 9, < ordinary characters just match themselves exactly.
2	. (a period) matches any single character except newpne
3	w matches a "word" character: a letter or digit or underbar [a-zA-Z0-9_].
4	W matches any non-word character.
5	boundary between word and non-word
6	s matches a single whitespace character -- space, newpne, return, tab
7	S matches any non-whitespace character.
8	, , tab, newpne, return
9	d decimal digit [0-9]
10	^ matches start of the string
11	&dollar; match the end of the string
12	inhibit the "specialness" of a character.