Python: Convert string with comma separator and dot to float

# Table of Contents

# Python: Convert string with comma separator and dot to float

To convert a string with a comma separator and dot to a float:

Use the locale.setlocale() method to set the locale to en_US.UTF-8.
Use the locale.atof() method to convert the string to a float.

main.py

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import locale


# ✅ Convert string with comma separator and dot to float (locale.atof())
locale.setlocale(locale.LC_ALL, 'en_US.UTF-8')

my_str = '456,789.4567'

result = locale.atof(my_str)
print(result)  # 👉️ 456789.4567

convert string with comma separator and dot to float

The code for this article is available on GitHub

The example uses the locale.atof() method to convert the string with a comma and dot to a float.

We used the locale.setlocale() method to set the locale to en_US.UTF-8.

main.py

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import locale

locale.setlocale(locale.LC_ALL, 'en_US.UTF-8')

The setlocale() method takes the category and the locale.

The locale.LC_ALL category sets the locale for all categories.

# Using the user's preferred locale

You can also set the locale to an empty string to use the user's preferred locale.

main.py

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import locale


# ✅ Convert string with comma separator and dot to float (locale.atof())
locale.setlocale(locale.LC_ALL, '')

my_str = '456,789.4567'

result = locale.atof(my_str)
print(result)  # 👉️ 456789.4567

using users preferred locale

The code for this article is available on GitHub

When the locale.LC_ALL attribute is set to an empty string, the user's preferred locale is used.

The thousands separator character in the United States is a comma, so that's what we set the locale parameter to.

The locale.atof() method takes a string and converts it to a floating-point number.

main.py

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import locale

locale.setlocale(locale.LC_ALL, '')

my_str = '456,789.4567'

result = locale.atof(my_str)
print(result)  # 👉️ 456789.4567

Make sure to use the setlocale() method before calling the locale.atof() method.

This approach would also work if the string has underscore separators instead of commas.

main.py

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import locale


locale.setlocale(locale.LC_ALL, '')

my_str = '456_789_123.4567'

result = locale.atof(my_str)
print(result)  # 👉️ 456789123.4567

Alternatively, you can use the str.replace() method.

# Python: Convert string with comma separator and dot to float using replace()

This is a two-step process:

Use the str.replace() method to remove the commas from the string.
Use the float() class to convert the string to a floating-point number.

main.py

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my_str = '456,789.4567'


result = float(my_str.replace(',', ''))
print(result)  # 👉️ 456789.4567

convert string with comma and dot to float using replace

The code for this article is available on GitHub

The str.replace() method returns a copy of the string with all occurrences of a substring replaced by the provided replacement.

The method takes the following parameters:

Name	Description
old	The substring we want to replace in the string
new	The replacement for each occurrence of `old`
count	Only the first `count` occurrences are replaced (optional)

The method doesn't change the original string. Strings are immutable in Python.

Once the commas are removed from the string, we can use the float() class to convert it to a floating-point number.

Note that in some locales a comma is used as the thousands separator (e.g. in the United States) and in some other locales a comma is used as the decimal separator (e.g. France).

If a comma is used as the decimal point, call the replace() method twice.

main.py

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my_str = '456.789,4567'


result = float(my_str.replace('.', '').replace(',', '.'))
print(result)  # 👉️ 456789.4567

The first call to the replace method removes the period . from the string.

The second call replaces the comma with a period.

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Python: Convert string with comma separator and dot to float

# Table of Contents

# Python: Convert string with comma separator and dot to float

# Using the user's preferred locale

# Python: Convert string with comma separator and dot to float using replace()

# Additional Resources

Borislav Hadzhiev