# How To Convert a String to a Float in Python

Published on August 3, 2022 · Updated on September 21, 2022 By Pankaj ### Introduction

In this article, we will use Python’s `float()` function to convert strings to floats. And we will also use Python’s `str()` function to convert floats to strings.

It is important to properly convert the data types before using them for calculations and concatenations in order to prevent runtime errors.

## Prerequisites

In order to complete this tutorial, you will need:

This tutorial was tested with Python 3.9.6.

## Using the `float()` function

We can convert a string to float in Python using the `float()` function. This is a built-in function used to convert an object to a floating point number. Internally, the `float()` function calls specified object `__float__()` function.

### Example

Let’s look at an example of converting a string to float in Python:

``````input_1 = '10.5674'

input_1 = float(input_1)

print(type(input_1))
print('Float Value =', input_1)
``````

Output:

``````<class 'float'>
Float Value = 10.5674
``````

The string value of `'10.5674'` has been converted to a float value of `10.5674`.

### Why do we need to convert a string to float?

If we are receiving float value from user input through the terminal or reading it from a file, then they are string objects. We have to explicitly convert them to float so that we can perform necessary operations on them, such as addition, multiplication, etc.

``````input_1 = input('Please enter first floating point value:\n')
input_1 = float(input_1)

input_2 = input('Please enter second floating point value:\n')
input_2 = float(input_2)

print(f'Sum of {input_1} and {input_2} is {input_1+input_2}')
``````

Note: If you are not familiar with string formatting using f prefix, please read f-strings in Python.

Let’s run this code and provide float values for `input_1` and `input_2`:

``````Please enter first floating point value:
10.234
Please enter second floating point value:
2.456
Sum of 10.234 and 2.456 is 12.69
``````

The resulting sum of `10.234` and `2.456` is `12.69`.

Ideally, we should use a `try-except` block to catch exceptions in case of invalid input from the user.

## Using the `str()` function

We can also convert a float to a string using the `str()` function. This might be required in situations where we want to concatenate float values.

### Example

Let’s look at an example:

``````input_1 = 10.23
input_2 = 20.34
input_3 = 30.45

# using f-string from Python 3.6+, change to format() for older versions
print(f'Concatenation of {input_1} and {input_2} is {str(input_1) + str(input_2)}')
print(f'CSV from {input_1}, {input_2} and {input_3}:\n{str(input_1)},{str(input_2)},{str(input_3)}')
print(f'CSV from {input_1}, {input_2} and {input_3}:\n{", ".join([str(input_1),str(input_2),str(input_3)])}')
``````

Let’s run this code:

``````Concatenation of 10.23 and 20.34 is 10.2320.34
CSV from 10.23, 20.34 and 30.45:
10.23,20.34,30.45
CSV from 10.23, 20.34 and 30.45:
10.23, 20.34, 30.45
``````

Concatenating `10.23` and `20.34` produces the string `'10.2320.34'`. This code also produces two versions of comma-separated values (CSV).

If we don’t convert float to string in the above program, the `join()` function will throw an exception. Also, we won’t be able to use the `+` operator to concatenate as it will add the floating point numbers.

## Conclusion

You can check out the complete Python script and more Python examples from our GitHub repository.

References:

Thanks for learning with the DigitalOcean Community. Check out our offerings for compute, storage, networking, and managed databases. Pankaj

author

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