Python Regex to only include/extract numbers, decimals and Hyphen (-)

August 29, 2024

I am not good at regex and have been trying & failing to extract only numbers, decimals and - from a column in python.

Even better if spaces can also be removed but if not even then it is still manageable.

I have tested ^(\d.+)|[-] and ^(\d.+)|[-]?[^a-z]+$/i and ^(\d.+)|[-]?(\d+)? but none of them worked correctly.

Test Cases (Basically these are Ranges from inconsistent format)

28193.13
28913
28913-13
28193.13-28193.13
28193.13 - 28193.13
28193.13 - 28193.13 / cm
 - 28193.13
 -28193.13
 28913-
 28913 -

Desired Results on above cases:

28193.13
28913
28913-13
28193.13-28193.13
28193.13-28193.13
28193.13-28193.13
-28193.13
-28193.13
28913-
28913-

Issue: I am unable to remove characters from this 28193.13 - 28193.13 / cm with my regex code as the desired result from this would be 28193.13-28193.13.

Tool: I have used this regex test website to test regex code

Appreciate any help.

>Solution :

I think this is a good fix with regex.


    # Define the regex pattern to match numbers, decimals, and hyphens
    pattern = r"[\d\.]+(?:-\d+)?"
    # Find all matches
    matches = re.findall(pattern, value)
    # Join matches to form the cleaned value
    cleaned_value = ''.join(matches)
    return cleaned_value

You can also sovle this a bit more robustly:

def clean_value(value):
    # Filter out characters that are not digits, period, or hyphen
    cleaned_value = ''.join([char for char in value if char.isdigit() or char in ['.', '-']])
    return cleaned_value

# Apply the cleaning function to the data
cleaned_data = [clean_value(val) for val in data]```