# Convert String to Int Python

In Python, strings can be converted into an integer using built-in functions like ‘int()’, ‘eval()’, ‘str.isdigit()’, etc. However, it’s important to note that the string must represent a valid integer value for the conversion to succeed.

We will look at methods to change datatype from string to int in Python.

Example

```Input: str_num = "1001"
Output: 1001
Explanation: In this, we are converting string into integer```

## How to Convert String to Int?

There are several built-in functions in PythonSeveral built-in functions in Python that let you convert strings to numbers. These functions take a string as its argument and return the corresponding integer value.

## Convert String to Number Methods

We have explained the methods to convert a string into a integer datatype. Here is the list of the functions:

1. Using int() function
2. Using eval() function
3. Using ast.literal_eval
4. Using str.isdigit() function

### Convert string to int using int() Function

Here we will use int() function that will return the int data type.

## Python3

 `num ``=` `'10'` `# check and print type num variable``print``(``type``(num))` `# convert the num from string into int``converted_num ``=` `int``(num)` `# print type of converted_num``print``(``type``(converted_num))` `# We can check by doing some mathematical operations``print``(converted_num ``+` `20``)`

Output
```<class 'str'>
<class 'int'>
30
```

As a side note, to convert to float, we can use float() in Python

### Convert string to int using Eval() Function

Here we will use eval() methods to Convert String to Int

## Python3

 `# converting python string to``# int using eval() function``a ``=` `"100"``print``(``eval``(a)``+``12``)`

Output
```112
```

### String to Int Converter using Ast.literal_eval

This function evaluates an expression node or a string consisting of a Python literal or container display.

## Python3

 `from` `ast ``import` `literal_eval` `int_value ``=` `literal_eval(``"1234"``)``print``(int_value)``print``(``type``(int_value))`

Output
```1234
<class 'int'>
```

### Convert string to int using str.isdigit() Method

Python isdigit() function returns a boolean value TRUE if all the values in the input string are digits else it returns FALSE.

## Python3

 `string ``=` `"42"``if` `string.isdigit():``    ``integer ``=` `int``(string)``    ``print``(integer)  ``# Output: 42``else``:``    ``print``(f``"{string} is not a valid integer."``)`

Output
```42
```

Note: float values are decimal values that can be used with integers for computation.

We have covered the methods to convert string to int in Python. You can use any of the mentioned methods to change the data type of the variable from string to integer.

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