sed to python replace extra delimiters in a

Question

sed 's/\t/_tab_/3g'

I have a sed command that basically replaces all excess tab delimiters in my text document. My documents are supposed to be 3 columns, but occasionally there's an extra delimiter. I don't have control over the files.

I use the above command to clean up the document. However all my other operations on these files are in python. Is there a way to do the above sed command in python?

sample input:

Column1   Column2         Column3
James     1,203.33        comment1
Mike      -3,434.09       testing testing 123
Sarah     1,343,342.23    there   here

sample output:

Column1   Column2         Column3
James     1,203.33        comment1
Mike      -3,434.09       testing_tab_testing_tab_123
Sarah     1,343,342.23    there_tab_here

Answer 1

You may read the file line by line, split with tab, and if there are more than 3 items, join the items after the 3rd one with _tab_:

lines = []
with open('inputfile.txt', 'r') as fr:
    for line in fr:
        split = line.split('\t')
        if len(split) > 3:
            tmp = split[:2]                      # Slice the first two items
            tmp.append("_tab_".join(split[2:]))  # Append the rest joined with _tab_
            lines.append("\t".join(tmp))         # Use the updated line
        else:
            lines.append(line)                   # Else, put the line as is

See the Python demo

The lines variable will contain something like

Mike    -3,434.09   testing_tab_testing_tab_123
Mike    -3,434.09   testing_tab_256
No  operation   here