Convert sed with multiple expressions to python

Question

I have the following sed script:

cat foo.txt | sed -e "s/.*\[\([^]]*\)\].*/\1/g" -e "s/ //g" -e "s/'//g"

Which can be translated into three expressions:

1. Captures all text between [...]
2. Removes white-spaces
3. Removes all single quotes

What's a neat way to do something similar with a text file in python?

Answer 1

You could do it all with regular expressions (re.sub()) but this does it mostly with plain Python, just using regular expressions for the initial capture.

import re

s = "some string ['foo'] [b a r] [baz] [] extra stuff"

pat0 = re.compile(r'\[([^]]*)\]')

lst0 = pat0.findall(s)

lst1 = [s.replace(' ', '') for s in lst0]
lst2 = [s.replace("'", '') for s in lst1]

print(lst2) # prints: ['foo', 'bar', 'baz', '']

Answer 2

import re

with open('foo.txt', 'r') as f:
    read_data = f.readlines()
    out_data = []
    for line in read_data:
        out_line = re.sub(r".*\[([^]]*)\].*", r"\1", line)
        out_line = re.sub(r" ", r"", out_line)
        out_line = re.sub(r"'", r"", out_line)
        out_data.append(out_line)
    # do whatever you want with out_data here