How can I remove all non-numeric characters from all the values in a particular column in pandas dataframe?

Question

I have a dataframe which looks like this:

     A       B           C
1   red78   square    big235
2   green   circle    small123
3   blue45  triangle  big657         


        

Answer 1

To remove all non-digit characters from strings in a Pandas column you should use str.replace with \D+ or [^0-9]+ patterns:

dfObject['C'] = dfObject['C'].str.replace(r'\D+', '')

Or, since in Python 3, \D is fully Unicode-aware by default and thus does not match non-ASCII digits (like ۱۲۳۴۵۶۷۸۹, see proof) you should consider

dfObject['C'] = dfObject['C'].str.replace(r'[^0-9]+', '')

So,

import re
print ( re.sub( r'\D+', '', '1۱۲۳۴۵۶۷۸۹0') )         # => 1۱۲۳۴۵۶۷۸۹0
print ( re.sub( r'[^0-9]+', '', '1۱۲۳۴۵۶۷۸۹0') )     # => 10