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In this post, you will learn the feature and uses of `operators in python`

. Before we get started, if you want to Array in `Python`

, please go through the following article: Array.

**What are operators in python?**

Operators are special symbols in Python that carry out arithmetic or logical computation. The value that the operator operates on is called the operand. For example:

1 2 3 4 |
>>> 2+3 >>> 5 |

Here, `+`

is the operator that performs addition. `2`

and `3`

are the operands and `5`

is the output of the operation.

**Arithmetic operators**

Arithmetic operators are used to performing mathematical operations like addition, subtraction, multiplication, etc.

Operator | Meaning | Example |
---|---|---|

+ | Add two operands or unary plus | x + y+ 2 |

– | Subtract right operand from the left or unary minus | x – y- 2 |

* | Multiply two operands | x * y |

/ | Divide left operand by the right one (always results in float) | x / y |

% | Modulus – the remainder of the division of left operand by the right | x % y (remainder of x/y) |

// | Floor division – division that results into the whole number adjusted to the left in the number line | x // y |

** | Exponent – left operand raised to the power of right | x**y (x to the power y) |

##### Example 1: Arithmetic operators in Python

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x = 15 y = 4 # Output: x + y = 19 print('x + y =',x+y) # Output: x - y = 11 print('x - y =',x-y) # Output: x * y = 60 print('x * y =',x*y) # Output: x / y = 3.75 print('x / y =',x/y) # Output: x // y = 3 print('x // y =',x//y) # Output: x ** y = 50625 print('x ** y =',x**y) |

Output

1 2 3 4 5 6 7 8 |
x + y = 19 x - y = 11 x * y = 60 x / y = 3.75 x // y = 3 x ** y = 50625 |

**Comparison operators**

Comparison operators are used to comparing values. It returns either `True`

or `False`

according to the condition.

Operator | Meaning | Example |
---|---|---|

> | Greater than – True if left operand is greater than the right | x > y |

< | Less than – True if left operand is less than the right | x < y |

== | Equal to – True if both operands are equal | x == y |

!= | Not equal to – True if operands are not equal | x != y |

>= | Greater than or equal to – True if left operand is greater than or equal to the right | x >= y |

<= | Less than or equal to – True if left operand is less than or equal to the right | x <= y |

##### Example 2: Comparison operators in Python

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x = 10 y = 12 # Output: x > y is False print('x > y is',x>y) # Output: x < y is True print('x < y is',x<y) # Output: x == y is False print('x == y is',x==y) # Output: x != y is True print('x != y is',x!=y) # Output: x >= y is False print('x >= y is',x>=y) # Output: x <= y is True print('x <= y is',x<=y) |

Output

1 2 3 4 5 6 7 8 |
x > y is False x < y is True x == y is False x != y is True x >= y is False x <= y is True |

**Logical operators**

Logical operators are the `and`

, `or`

, `not`

operators.

Operator | Meaning | Example |
---|---|---|

and | True if both the operands are true | x and y |

or | True if either of the operands is true | x or y |

not | True if operand is false (complements the operand) | not x |

##### Example 3: Logical Operators in Python

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x = True y = False print('x and y is',x and y) print('x or y is',x or y) print('not x is',not x) |

Output

1 2 3 4 5 6 7 |
x and y is False x or y is True not x is False |

Here is the truth table for these operators.

**Bitwise operators**

Bitwise operators act on operands as if they were strings of binary digits. They operate bit by bit, hence the name. For example, 2 is `10`

in binary and 7 is `111`

. In the table below: Let `x` = 10 (`0000 1010`

in binary) and `y` = 4 (`0000 0100`

in binary)

Operator | Meaning | Example |
---|---|---|

& | Bitwise AND | x & y = 0 (`0000 0000` ) |

| | Bitwise OR | x | y = 14 (`0000 1110` ) |

~ | Bitwise NOT | ~x = -11 (`1111 0101` ) |

^ | Bitwise XOR | x ^ y = 14 (`0000 1110` ) |

>> | Bitwise right shift | x >> 2 = 2 (`0000 0010` ) |

<< | Bitwise left shift | x << 2 = 40 (`0010 1000` ) |

**Assignment operators**

Assignment operators are used in Python to assign values to variables. `a = 5`

is a simple assignment operator that assigns the value 5 on the right to the variable `a` on the left. There are various compound operators in Python like `a += 5`

that adds to the variable and later assigns the same. It is equivalent to `a = a + 5`

.

Operator | Example | Equivalent to |
---|---|---|

= | x = 5 | x = 5 |

+= | x += 5 | x = x + 5 |

-= | x -= 5 | x = x – 5 |

*= | x *= 5 | x = x * 5 |

/= | x /= 5 | x = x / 5 |

%= | x %= 5 | x = x % 5 |

//= | x //= 5 | x = x // 5 |

**= | x **= 5 | x = x ** 5 |

&= | x &= 5 | x = x & 5 |

|= | x |= 5 | x = x | 5 |

^= | x ^= 5 | x = x ^ 5 |

>>= | x >>= 5 | x = x >> 5 |

<<= | x <<= 5 | x = x << 5 |

**Special operators**

Python language offers some special types of operators like the identity operator or the membership operator. They are described below with examples.

##### Identity operators

`is`

and `is not`

are the identity operators in Python. They are used to check if two values (or variables) are located on the same part of the memory. Two variables that are equal does not imply that they are identical.

Operator | Meaning | Example |
---|---|---|

is | True if the operands are identical (refer to the same object) | x is True |

is not | True if the operands are not identical (do not refer to the same object) | x is not True |

##### Example 4: Identity operators in Python

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 |
x1 = 5 y1 = 5 x2 = 'Hello' y2 = 'Hello' x3 = [1,2,3] y3 = [1,2,3] # Output: False print(x1 is not y1) # Output: True print(x2 is y2) # Output: False print(x3 is y3) |

Output

1 2 3 4 5 |
False True False |

Here, we see that `x1` and `y1` are integers of the same values, so they are equal as well as identical. Same is the case with `x2` and `y2` (strings). But `x3` and `y3` are lists. They are equal but not identical. It is because the interpreter locates them separately in memory although they are equal.

##### Membership operators

`in`

and `not in`

are the membership operators in Python. They are used to test whether a value or variable is found in a sequence (string, list, tuple, set and dictionary). In a dictionary we can only test for presence of key, not the value.

Operator | Meaning | Example |
---|---|---|

in | True if value/variable is found in the sequence | 5 in x |

not in | True if value/variable is not found in the sequence | 5 not in x |

##### Example #5: Membership operators in Python

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x = 'Hello world' y = {1:'a',2:'b'} # Output: True print('H' in x) # Output: True print('hello' not in x) # Output: True print(1 in y) # Output: False print('a' in y) |

Output

1 2 3 4 5 6 |
True True True False |

Here, `'H'`

is in `x` but `'hello'`

is not present in `x` (remember, Python is case sensitive). Similarly, `1`

is key and `'a'`

is the value in dictionary `y`. Hence, `'a' in y`

returns `False`

.

The article was published on September 22, 2020 @ 2:14 PM

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