An operator is a symbol that performs an operation on values and variables. You can use the following operator types in Python:
- Arithmetic Operators
- Comparison Operators
- Assignment Operators
- Logical Operators
- Bitwise Operators
- Membership Operators
- Identity Operators
Arithmetic Operators
Arithmetic operators are used to perform arithmetic operations like addition, subtraction, multiplication, division, etc.
| Operator | Description | Format | Example |
|---|---|---|---|
| + | Addition | a + b | 3 + 5 = 8 |
| – | Subtraction | a – b | 10 – 7 = 3 |
| * | Multiplication | a * b | 3 * 4 = 12 |
| / | Division | a / b | 21 / 7 = 3 |
| & | Modulus | a % b | 23 % 7 = 2 |
| ** | Exponent | a ** b | 2 * 4 = 16 |
| // | Floor Division – Rounds down to nearest whole number | a // b | 9 // 2 = 4 -9 // 2 = -5 |
Comparison Operators
Comparison operators are used to compare two values and return a boolean result (true/false).
| Operator | Description | Format | Example |
|---|---|---|---|
| == | Equality | a == b | 5 == 5 |
| != | Inequality | a != b | 3 != 5 |
| > | Greater than | a > b | 5 > 3 |
| < | Less tahn | a < b | 3 < 5 |
| >= | Greater than or equal to | a >= b | 5 >= 3 |
| <= | Less than or equal to | a <= b | 3 <= 5 |
In Python 2, both != and <> are used as Inequality Operator (a != b) (a <> b).
In Python 3, <> is removed, only != is used for inequality comparison.
Assignment Operators
Assignment operators are used to assign right-side expressions to left-side variables.
| Operator | Description | Format | Equivalent to |
|---|---|---|---|
| = | Assignment | a = b | a = b |
| += | Addition and Assignment | a += b | a = a + b |
| -= | Subtraction and Assignment | a -= b | a = a – b |
| *= | Multiplication and Assignment | a *= b | a = a * b |
| /= | Division and Assignment | a /= b | a = a / b |
| %= | Modulus and Assignment | a %= b | a = a % b |
| **= | Exponent and Assignment | a **= b | a = a ** b |
| =// | Floor Division and Assignment | a //= b | a = a // b |
Logical Operators
There are 3 logical operators in Python: AND, OR and NOT. These operators are mainly used in conditional statements.
| Operator | Description | Format | Example |
|---|---|---|---|
| AND | If both the expression are true, then returns TRUE | condition1 AND contidion2 | (6 > 5) AND (5 > 4) returns TRUE |
| OR | If at least one of the expressions is true, then returns TRUE | condition1 OR contidion2 | (5 > 4) OR (4 > 5) returns TRUE |
| NOT | If condition is true, returns FALSE If condition is false, returns TRUE | NOT(condition) | NOT(5 > 4) returns FALSE |
Bitwise Operators
Bitwise operators are used to perform operations on individual bits in a number.
| Operator | Description | Format |
|---|---|---|
| & (AND) | If both bits are 1, resulting bit will be 1 | 1010 & 0101 = 1111 |
| | (OR) | If either of the bits is 1, resulting bit will be 1 | 1010 | 1001 = 1011 |
| ^ (XOR) | If only one of the bits is 1, resulting bit will be 1 | 1010 ^ 1001 = 0011 |
| ~ (Bitwise Inversion) | This operator calculates ones’ complement of the number | ~1100 = -1101 |
| << (Left shift) | Each bit in a number is shifted to left | 0001101 << 2 = 0110100 |
| (Right shift) | Each bit in a number is shifted to right | 0110100 >> 2 = 0001101 |
Bitwise Inversion of a number x is calculated as -(x+1). For instance, bitwise inversion of 151 (10010111) is -152 (-10011000).
Membership Operators
Membership operators are used to check the appearance of a value within a sequence like lists, strings or tuples. There are two membership operators in Python: IN, NOT IN
For the examples below consider prime list is defined as:
primes = [2, 3, 5, 7, 11]
| Operator | Description | Format | Example |
|---|---|---|---|
| IN | Returns TRUE if the value appears in the sequence | a in b | print(7 in primes) returns TRUE |
| NOT IN | Returns TRUE if the value does not appear in the sequence | a not in b | print(4 not in primes) returns TRUE |
Identity Operators
Identity operators are used to check whether two objects refer to the same object. There are two identity operators in Python: IS, IS NOT
For the examples below consider the code below. Both var1 and var2 have the same content but they are distinct objects in memory. var3, on the other hand, refers to the same object as var1.
var1 = ["Hello", "World"]
var2 = ["Hello", "World"]
var3 = var1
print(var1 is var2)
print(var1 is var3)
| Operator | Description | Format | Example |
|---|---|---|---|
| IS | Returns TRUE if both operands refer to the same object | a is b | var1 is var2 returns FALSEvar1 is var3 returns TRUE |
| IS NOT | Returns TRUE if the operands are different objects | a is not b | var1 is not var2 returns TRUE |
You can also use identity operators to check the type of an object.
Since the type of var1 is list, following code prints TRUE.
print(type(var1) is list)