Python

 

Python is an interpreted high-level general-purpose programming language.Python's design philosophy emphasizes code readability with its notable use of significant indentation.Its language constructs as well as its object-oriented approach aim to help programmers write clear, logical code for small and large-scale projects. Python is dynamically-typed and garbage-collected. Python is a programming language. Python can be used on a server to create web applications. Start learning Python now ». Python was created in the early 1990s by Guido van Rossum at Stichting Mathematisch Centrum in the Netherlands as a successor of a language called ABC. Guido remains Python’s principal author, although it includes many contributions from others. Python supports a wide range of arithmetic operators that you can use when working with numbers in your code. One of these operators is the modulo operator (%), which returns the remainder of dividing two numbers. In this tutorial, you’ll learn: How modulo works in mathematics; How to use the Python modulo operator with different numeric types.

Python Install

Many PCs and Macs will have python already installed.

To check if you have python installed on a Windows PC, search in the start bar for Python or run the following on the Command Line (cmd.exe):

To check if you have python installed on a Linux or Mac, then on linux open the command line or on Mac open the Terminal and type:

If you find that you do not have python installed on your computer, then you can download it for free from the following website: https://www.python.org/

Python Quickstart

Python is an interpreted programming language, this means that as a developer you write Python (.py) files in a text editor and then put those files into the python interpreter to be executed.

The way to run a python file is like this on the command line:

Where 'helloworld.py' is the name of your python file.

Let's write our first Python file, called helloworld.py, which can be done in any text editor.

helloworld.py

PythonTry it Yourself »

Simple as that. Save your file. Open your command line, navigate to the directory where you saved your file, and run:

The output should read:

Congratulations, you have written and executed your first Python program.

The Python Command Line

To test a short amount of code in python sometimes it is quickest and easiest not to write the code in a file. This is made possible because Python can be run as a command line itself.

Type the following on the Windows, Mac or Linux command line:

Or, if the 'python' command did not work, you can try 'py':

From there you can write any python, including our hello world example from earlier in the tutorial:

C:UsersYour Name>python
Python 3.6.4 (v3.6.4:d48eceb, Dec 19 2017, 06:04:45) [MSC v.1900 32 bit (Intel)] on win32
Type 'help', 'copyright', 'credits' or 'license' for more information.

>>> print('Hello, World!')
Python

Which will write 'Hello, World!' in the command line:

Download Python 3.9

C:UsersYour Name>python
Python 3.6.4 (v3.6.4:d48eceb, Dec 19 2017, 06:04:45) [MSC v.1900 32 bit (Intel)] on win32
Type 'help', 'copyright', 'credits' or 'license' for more information.
>>> print('Hello, World!')

Hello, World!

Whenever you are done in the python command line, you can simply type the following to quit the python command line interface:


  • Python Basic Tutorial
  • Python Advanced Tutorial
  • Python Useful Resources
  • Selected Reading

Operators are the constructs which can manipulate the value of operands.

Consider the expression 4 + 5 = 9. Here, 4 and 5 are called operands and + is called operator.

Types of Operator

Python language supports the following types of operators.

  • Arithmetic Operators
  • Comparison (Relational) Operators
  • Assignment Operators
  • Logical Operators
  • Bitwise Operators
  • Membership Operators
  • Identity Operators

Let us have a look on all operators one by one.

Python Arithmetic Operators

Assume variable a holds 10 and variable b holds 20, then −

[ Show Example ]

OperatorDescriptionExample
+ AdditionAdds values on either side of the operator.a + b = 30
- SubtractionSubtracts right hand operand from left hand operand.a – b = -10
* MultiplicationMultiplies values on either side of the operatora * b = 200
/ DivisionDivides left hand operand by right hand operandb / a = 2
% ModulusDivides left hand operand by right hand operand and returns remainderb % a = 0
** ExponentPerforms exponential (power) calculation on operatorsa**b =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. 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

Python Comparison Operators

These operators compare the values on either sides of them and decide the relation among them. They are also called Relational operators.

Assume variable a holds 10 and variable b holds 20, then −

[ Show Example ]

OperatorDescriptionExample
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 values of two operands are not equal, then condition becomes true.(a <> b) is true. This is similar to != operator.
>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.

Python Assignment Operators

Assume variable a holds 10 and variable b holds 20, then −

Pycharm

[ Show Example ]

OperatorDescriptionExample
=Assigns values from right side operands to left side operandc = a + b assigns value of a + b into c
+= Add ANDIt adds right operand to the left operand and assign the result to left operandc += a is equivalent to c = c + a
-= Subtract ANDIt subtracts right operand from the left operand and assign the result to left operandc -= a is equivalent to c = c - a
*= Multiply ANDIt multiplies right operand with the left operand and assign the result to left operandc *= a is equivalent to c = c * a
/= Divide ANDIt divides left operand with the right operand and assign the result to left operandc /= a is equivalent to c = c / a
%= Modulus ANDIt takes modulus using two operands and assign the result to left operandc %= a is equivalent to c = c % a
**= Exponent ANDPerforms exponential (power) calculation on operators and assign value to the left operandc **= a is equivalent to c = c ** a
//= Floor DivisionIt performs floor division on operators and assign value to the left operandc //= a is equivalent to c = c // a

Python Bitwise Operators

Bitwise operator works on bits and performs bit by bit operation. Assume if a = 60; and b = 13; Now in the binary format their values will be 0011 1100 and 0000 1101 respectively. Following table lists out the bitwise operators supported by Python language with an example each in those, we use the above two variables (a and b) as operands −

a = 0011 1100

b = 0000 1101 An acceptable time pdf free download.

-----------------

a&b = 0000 1100

a b = 0011 1101

a^b = 0011 0001

~a = 1100 0011

There are following Bitwise operators supported by Python language

[ Show Example ]

OperatorDescriptionExample
& Binary ANDOperator copies a bit to the result if it exists in both operands(a & b) (means 0000 1100)
Binary ORIt copies a bit if it exists in either operand.(a b) = 61 (means 0011 1101)
^ Binary XORIt copies the bit if it is set in one operand but not both.(a ^ b) = 49 (means 0011 0001)
~ Binary Ones ComplementIt is unary and has the effect of 'flipping' bits.(~a ) = -61 (means 1100 0011 in 2's complement form due to a signed binary number.
<< Binary Left ShiftThe left operands value is moved left by the number of bits specified by the right operand.a << 2 = 240 (means 1111 0000)
>> Binary Right ShiftThe left operands value is moved right by the number of bits specified by the right operand.a >> 2 = 15 (means 0000 1111)

Python Logical Operators

There are following logical operators supported by Python language. Assume variable a holds 10 and variable b holds 20 then

[ Show Example ]

OperatorDescriptionExample
and Logical ANDIf both the operands are true then condition becomes true.(a and b) is true.
or Logical ORIf any of the two operands are non-zero then condition becomes true.(a or b) is true.
not Logical NOTUsed to reverse the logical state of its operand.Not(a and b) is false.

Python Membership Operators

Python’s membership operators test for membership in a sequence, such as strings, lists, or tuples. There are two membership operators as explained below −

[ Show Example ]

Python Download

OperatorDescriptionExample
inEvaluates 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 inEvaluates 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.

Python Identity Operators

Identity operators compare the memory locations of two objects. There are two Identity operators explained below −

[ Show Example ]

OperatorDescriptionExample
isEvaluates 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 notEvaluates 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).

Python Operators Precedence

The following table lists all operators from highest precedence to lowest.

[ Show Example ]

Sr.No.Operator & Description
1

**

Exponentiation (raise to the power)

2

~ + -

Complement, unary plus and minus (method names for the last two are [email protected] and [email protected])

3

* / % //

Multiply, divide, modulo and floor division

4

+ -

Addition and subtraction

5

>> <<

Right and left bitwise shift

6

&

Bitwise 'AND'

7

^

Bitwise exclusive `OR' and regular `OR'

8

<= < > >=

Comparison operators

9

<> !=

Equality operators

10

= %= /= //= -= += *= **=

Assignment operators

11

is is not

Identity operators

12

in not in

Membership operators

13

not or and

Logical operators