# Python int() Function

• Difficulty Level : Medium
• Last Updated : 25 Aug, 2022

Python int() function returns an integer from a given object or converts a number in a given base to a decimal.

## Python int() Function Syntax :

Syntax: int(x, base)

• x [optional]: string representation of integer value, defaults to 0, if no value provided.
• base [optional]: (integer value) base of the number.

Returns: Return decimal (base-10) representation of x

## Python3

 `age ``=` `"21"``print``(``"age ="``, ``int``(age))`

Output:

`age = 21`

### Example 1: Working with int() function in Python

Demonstrating usage of Python int() function on different data-types in Python.

## Python3

 `# int() on string representation of numbers``print``(``"int('9')) ="``, ``int``(``'9'``))`` ` `# int() on float values``print``(``"int(9.9) ="``, ``int``(``9.9``))`` ` `# int() on Python integer``print``(``"int(9) ="``, ``int``(``9``))`

Output :

```int('9')) = 9
int(9.9) = 9
int(9) = 9```

### Example 2: Convert base using Python int()

Convert numbers from different base to decimal using Python int()

## Python3

 `# octal to decimal using int()``print``(``"int() on 0o12 ="``, ``int``(``'0o12'``, ``8``))`` ` `# binary to decimal using int()``print``(``"int() on 0b110 ="``, ``int``(``'0b110'``, ``2``))`` ` `# hexa-decimal to decimal using int()``print``(``"int() on 0x1A ="``, ``int``(``'0x1A'``, ``16``))`

Output :

```int() on 0o12 = 10
int() on 0b110 = 6
int() on 0x1A = 26```

## Python int() Exception and Errors

TypeError : raises TypeError when any object that do not have __int__() or __index__() Python magic methods implemented.

ValueError: raises ValueError when any object cannot be converted to integer.

## Python3

 `print``(``int``(``0b101``, ``2``))`

Output :

`TypeError: int() can't convert non-string with explicit base`

## Python3

 `print``(``int``(``'geeks'``))`

Output:

`ValueError: invalid literal for int() with base 10: 'geeks'`

## Python int() Function on custom objects

### Example 1: int() with __int__() function

Python int() function can be used on any objects having implementation of __int__() function.

## Python3

 `class` `Number:``    ``value ``=` `7``     ` `    ``def` `__int__(``self``):``        ``return` `self``.value`` ` `data ``=` `Number()``print``(``"number ="``, ``int``(data))`

Output:

`number = 7`

### Example 2: int() with __index__() function

Python int() function can also be used on any objects having implementation of __index__() function.

## Python3

 `class` `Number:``    ``value ``=` `7``     ` `    ``def` `__index__(``self``):``        ``return` `self``.value`` ` `data ``=` `Number()``print``(``"number ="``, ``int``(data))`

Output:

`number = 7`

### Application:

It is used in all the standard conversions. For example, conversion of binary to decimal, octal to decimal, hexadecimal to decimal.

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