# Python int() Function

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

Example:

In this example, we passed a string as an argument to the int() function and printed it.

## Python3

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

Output:

`age = 21`

## Python int() Function Syntax

The syntax of the int() function in Python is as follows:

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

## Python int() Function Examples

Let us see a few examples of int() in Python.

### Python int() with different DataTypes

In this example, we passed a string, a float, and an integer value as a parameter to the int() function in Python to see how the input is affected by applying the int() function.

## 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```

### Convert base using int() in Python

In this example, we used the int() function to convert the base of a number from Binary, Octal, and Hexadecimal to a Decimal integer.

## 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```

## Exception of int() in Python

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

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

### TypeError: int() can’t convert non-string with explicit base

In this example, we are trying to convert a binary number to a decimal number using the Python int() function. But this code will raise an error as the binary number passed is not in a single quote.

## Python3

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

Output :

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

### ValueError: invalid literal for int() with base 10: ‘geeks’

This example will generate a value error as we are passing a Python String to the int() function.

## Python3

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

Output:

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

## Python int() Function for Custom Objects

The int() in Python can be used on custom objects. Let us see a few examples of the same.

### int() with __int__() function

In this example, we created a class called ‘Number’ and defined a value and a constructor that returns the value. Then we created an object called ‘data’ of the Number class which invokes the __init__() method. The data object stores the value that is returned by that method and then using the int() function we printed the value.

## Python3

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

Output:

`number = 7`

### int() with __index__() function

In this example, we created a class called ‘Number’ and defined a value and a function that returns the value. Then we created an object called ‘data’ of the Number class which invokes the __index__() method. The data object stores the value that is returned by that method and then using the int() function we printed the value.

## Python3

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

Output:

`number = 7`

### Application

The int() function in Python is used in all the standard conversions. For example, the conversion of binary to decimal, octal to decimal, and hexadecimal to decimal.

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