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# Convert string to integer in Python

In Python an strings can be converted into an integer using the built-in int() function. The int() function takes in any python data type and converts it into an integer.But use of the int() function is not the only way to do so. This type of conversion can also be done using the float() keyword, as a float value can be used to compute with integers. Below is the list of possible ways to convert an integer to string in python:

1. Using int() function

Syntax: int(string)

Example:

## 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

## Python3

 `num ``=` `'10.5'`` ` `# check and print type num variable``print``(``type``(num)) `` ` `# convert the num into string ``converted_num ``=` `float``(num)`` ` `# print type of converted_num``print``(``type``(converted_num))`` ` `# We can check by doing some mathematical operations``print``(converted_num ``+` `20.5``)`

Output

```<class 'str'>
<class 'float'>
31.0```

2. Using float() function

We first convert to float, then convert float to integer. Obviously the above method is better (directly convert to integer)

Syntax: float(string)

Example:

## Python3

 `a ``=` `'2'``b ``=` `'3'`` ` `# print the data type of a and b``print``(``type``(a))``print``(``type``(b))`` ` `# convert a using float``a ``=` `float``(a)`` ` `# convert b using int``b ``=` `int``(b)`` ` `# sum both integers``sum` `=` `a ``+` `b`` ` `# as strings and integers can't be added``# try testing the sum``print``(``sum``)`

Output

```<class 'str'>
<class 'str'>
5.0```

3. converting python string to int using eval() function

## Python3

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

Output

`112`

4. converting python string to float using eval() function

## Python3

 `# converting python string to ``# float using eval() function``a ``=` `"100.00"``print``(``eval``(a)``+``12``)`

Output

`112.0`

5. Using ast.literal_eval

## Python3

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

Output

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

6. Using str.isdigit()

## 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.

My Personal Notes arrow_drop_up