I need help defining the regex My inputs are like this

this is a paragraph with<[1> in between</[1> and then there are cases ... where the<[99> number ranges from 1-100</[99>.
and there are many other lines in the txt files
with<[3> such tags </[3>

The required output is

this is a paragraph with in between and then there are cases ... where the number ranges from 1-100.
and there are many other lines in the txt files
with such tags

I've tried this.

import os, sys, re, glob
for infile in glob.glob(os.path.join(os.getcwd(), '*.txt')):
    for line in reader:
        line2 = line.replace('<[1> ', '')
        line = line2.replace('</[1> ', '')
        line2 = line.replace('<[1>', '')
        line = line2.replace('</[1>', '')

        print line

I've also tried this but it seems to me that i'm using the wrong syntax

    line2 = line.replace('<[*> ', '')
    line = line2.replace('</[*> ', '')
    line2 = line.replace('<[*>', '')
    line = line2.replace('</[*>', '')

I dont want to hard-code the replace from 1 to 99 . . .

Best Answer

This tested sample should do it

import re
line = re.sub(r"</?\[\d+>", "", line)

Edit: Here's a commented version explaining how it works.

line = re.sub(r"""
  (?x) # Use free-spacing mode.
  <    # Match a literal '<'
  /?   # Optionally match a '/'
  \[   # Match a literal '['
  \d+  # Match one or more digits
  >    # Match a literal '>'
  """, "", line)

Regexes are fun! But I would strongly recommend spending an hour or two studying the basics. For starters, you need to learn which characters are special: "metacharacters" which need to be escaped (i.e. with a backslash placed in front - and the rules are different inside and outside character classes.) There is an excellent online tutorial at: www.regular-expressions.info . The time you spend there will pay for itself many times over. Happy regexing!