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Behavior of increment and decrement operators in Python

By IncludeHelp Last updated : December 08, 2024

Python Increment and Decrement Operators

Python is considered to be a consistent and readable language. Unlike in Java, python does not support the increment (++) and decrement (--) operators, both in precedence and in return value.

Example

For example, in python the x++ and ++x or x-- or --x is not valid.

x=1
x++

Output

  File "main.py", line 2
    x++
      ^
SyntaxError: invalid syntax

Example

x=1

print(--x)
# 1
print(++x)
# 1

print(x--)

'''
  File "/home/main.py", line 8
    print(x--)
             ^
SyntaxError: invalid syntax
'''

Reason for the above errors

The reason for this is, in Python integers are immutable and hence cannot be changed.

Implementing Increment and Decrement Operators

To implement increase and decrement operators in Python, you have to use the compound assignment with + and - signs. Use += to increment the variable's value and -= to decrement the variable's value. Or, simply perform the arithmetic operations (x = x + 1 to increment and x = x - 1 to decrement).

Example

# Initialize a variable with 10
x = 10

# Incrementing the value
x += 1
print(x)

# Decrementing the value
x -= 1
print(x)

# Incrementing the value
x += 1
print(x)

# Incrementing the value
x += 1
print(x)

Output

11
10
11
12