Python Operators: Arithmetic, Assignment, Comparison, Logical, Identity, Membership, Bitwise
Operators are special symbols that perform some operation on operands and returns the result. For example, 5 + 6 is an expression where + is an operator that performs arithmetic add operation on numeric left operand 5 and the right side operand 6 and returns a sum of two operands as a result.
Python includes the operator module that includes underlying methods for each operator. For example, the + operator calls the operator.add(a,b) method.
import operator
n=5+5
print(n)
n=operator.add(5, 10)
print(n)
n=operator.__add__(5, 20)
print(n)
Above, expression 5 + 6 is equivalent to the expression operator.add(5, 6) and operator.__add__(5, 6).
Many function names are those used for special methods, without the double underscores (dunder methods).
For backward compatibility, many of these have functions with the double underscores kept.
Python includes the following categories of operators:
- Arithmetic Operators
- Assignment Operators
- Comparison Operators
- Logical Operators
- Identity Operators
- Membership Test Operators
- Bitwise Operators
Arithmetic Operators
Arithmetic operators perform the common mathematical operation on the numeric operands.
The arithmetic operators return the type of result depends on the type of operands, as below.
- If either operand is a complex number, the result is converted to complex;
- If either operand is a floating point number, the result is converted to floating point;
- If both operands are integers, then the result is an integer and no conversion is needed.
The following table lists all the arithmetic operators in Python:
| Operation | Operator | Function | Example in Python Shell |
|---|---|---|---|
| Addition: Sum of two operands | + | operator.add(a,b) |
x,y= 5,6 print(x + y) #output: 11 import operator operator.add(5,6) #output: 11 |
| Subtraction: Left operand minus right operand | - | operator.sub(a,b) |
x,y =5,6 print(x - y) #output: -1 import operator operator.sub(10, 5) #output: 5 |
| Multiplication | * | operator.mul(a,b) |
x,y =5,6 print(x * y) #output: 30 import operator operator.mul(5,6) #output: 30 |
| Exponentiation: Left operand raised to the power of right | ** | operator.pow(a,b) |
x = 2; y = 3 print(x ** y) #output: 8 import operator operator.pow(2, 3) #output: 8 |
| Division | / | operator.truediv(a,b) |
x = 6; y = 3 print(x / y) #output: 2 import operator operator.truediv(6, 3) #output: 2 |
Floor division: equivilant to math.floor(a/b)
|
// | operator.floordiv(a,b) |
x = 6; y = 5 print(x // y) #output: 1 import operator operator.floordiv(6,5) #output: 1 |
Modulus: Reminder of a/b
|
% | operator.mod(a, b) |
x = 11; y = 3 print(x % y) #output: 12 import operator operator.mod(11, 3) #output: 2 |
Assignment Operators
The assignment operators are used to assign values to variables. The following table lists all the arithmetic operators in Python:
| Operator | Function | Example in Python Shell |
|---|---|---|
| = |
x = 5; x 5 |
|
| += | operator.iadd(a,b) |
x = 5 print(x += 5) #output: 10 import operator x = operator.iadd(5, 5) #output: 10 |
| -= | operator.isub(a,b) |
x = 5 print(x -= 2) #output: 3 import operator x = operator.isub(5,2) |
| *= | operator.imul(a,b) |
x = 2 print(x *= 3) #output: 6 import operator x = operator.imul(2, 3) |
| /= | operator.itruediv(a,b) |
x = 6 print(x /= 3) #output: 2 import operator x = operator.itruediv(6, 3) |
| //= | operator.ifloordiv(a,b) |
x = 6 print(x //= 5) #output: 1 import operator operator.ifloordiv(6,5) |
| %= | operator.imod(a, b) |
x = 11 print(x %= 3) #output: 2 import operator operator.imod(11, 3) #output: 2 |
| &= | operator.iand(a, b) |
x = 11 print(x &= 3) #output: 1 import operator operator.iand(11, 3) #output: 1 |
| |= | operator.ior(a, b) |
x = 3 print(x |= 4) #output: 7 import operator operator.mod(3, 4) #output: 7 |
| ^= | operator.ixor(a, b) |
x = 5 print(x ^= 2) #output: 7 import operator operator.ixor(5, 2) #output: 7 |
| >>= | operator.irshift(a, b) |
x = 5 print(x >>= 2) #output: 1 import operator operator.irshift(5, 2) #output: 1 |
| <<= | operator.ilshift(a, b) |
x = 5 print(x <<= 2) #output: 20 import operator operator.ilshift(5, 2) #output: 20 |
Comparison Operators
The comparison operators compare two operands and return a boolean either True or False. The following table lists comparison operators in Python.
| Operator | Function | Description | Example in Python Shell |
|---|---|---|---|
| > | operator.gt(a,b) | True if the left operand is higher than the right one |
x,y =5,6 print(x > y) #output: False import operator operator.gt(5,6) #output: False |
| < | operator.lt(a,b) | True if the left operand is lower than right one |
x,y =5,6 print(x < y) #output: True import operator operator.add(5,6) #output: True |
| == | operator.eq(a,b) | True if the operands are equal |
x,y =5,6 print(x == y) #output: False import operator operator.eq(5,6) #output: False |
| != | operator.ne(a,b) | True if the operands are not equal |
x,y =5,6 print(x != y) #output: True import operator operator.ne(5,6) #output: True |
| >= | operator.ge(a,b) | True if the left operand is higher than or equal to the right one |
x,y =5,6 print(x >= y) #output: False import operator operator.ge(5,6) #output: False |
| <= | operator.le(a,b) | True if the left operand is lower than or equal to the right one |
x,y =5,6 print(x <= y) #output: True import operator operator.le(5,6) #output: True |
Logical Operators
The logical operators are used to combine two boolean expressions. The logical operations are generally applicable to all objects, and support truth tests, identity tests, and boolean operations.
| Operator | Description | Example |
|---|---|---|
| and | True if both are true |
x,y =5,6 print(x > 1 and y <10) #output: True |
| or | True if at least one is true |
x,y =5,6 print(x > 6 or y <10) #output: True |
| not | Returns True if an expression evalutes to false and vice-versa |
x = 5 print(not x > 1) #output: False |
Identity Operators
The identity operators check whether the two objects have the same id value e.i. both the objects point to the same memory location.
| Operator | Function | Description | Example in Python Shell |
|---|---|---|---|
| is | operator.is_(a,b) | True if both are true |
x,y =5,6 print(x is y) #output: False import operator operator.is_(x,y) #output: False |
| is not | operator.is_not(a,b) | True if at least one is true |
x,y =5,6 print(x is not y) #output: True import operator operator.is_not(x, y) #output: True |
Membership Test Operators
The membership test operators in and not in test whether the sequence has a given item or not.
For the string and bytes types, x in y is True if and only if x is a substring of y.
| Operator | Function | Description | Example in Python Shell |
|---|---|---|---|
| in | operator.contains(a,b) | Returns True if the sequence contains the specified item else returns False. |
nums = [1,2,3,4,5]
print(1 in nums) #output: True
print(10 in nums) #output: False
print('str' in 'string') #output: True
import operator
operator.contains(nums, 2) #output: True
|
| not in | not operator.contains(a,b) | Returns True if the sequence does not contains the specified item, else returns False. |
nums = [1,2,3,4,5]
print(1 not in nums) #output: False
print(10 not in nums) #output: True
print('str' not in 'string') #output: False
import operator
not operator.contains(nums, 2) #output: False
|
Bitwise Operators
Bitwise operators perform operations on binary operands.
| Operator | Function | Description | Example in Python Shell |
|---|---|---|---|
| & | operator.and_(a,b) | Sets each bit to 1 if both bits are 1. |
x=5; y=10 z=x & y print(z) #output: 0 import operator operator.and_(x, y) |
| | | operator.or_(a,b) | Sets each bit to 1 if one of two bits is 1. |
x=5; y=10 z=x | y print(z) #output: 15 import operator operator.or_(x, y) |
| ^ | operator.xor(a,b) | Sets each bit to 1 if only one of two bits is 1. |
x=5; y=10 z=x ^ y print(z) #output: 15 import operator operator.xor(x, y) |
| ~ | operator.invert(a) | Inverts all the bits. |
x=5 print(~x) #output: -6 import operator operator.invert(x) |
| << | operator.lshift(a,b) | Shift left by pushing zeros in from the right and let the leftmost bits fall off. |
x=5 print(x<<2) #output: 20 import operator operator.lshift(x,2) |
| >> | operator.rshift(a,b) | Shift right by pushing copies of the leftmost bit in from the left, and let the rightmost bits fall off. |
x=5 print(x>>2) #output: 1 import operator operator.rshift(x,2) |
