How to Extract Text Between Strings Using Regular Expressions?

Matching Text Between Strings Using Regular Expressions

When working with text data, it's often necessary to extract specific portions based on predefined patterns or boundaries. One powerful tool for such tasks is regular expressions, allowing for precise and efficient text manipulation.

Consider the problem of extracting text between two specific strings. Given a string like "Part 1. Part 2. Part 3 then more text," the goal is to find and capture the text between "Part 1" and "Part 3."

The Regular Expression Approach

Python provides a comprehensive regular expression library that can be used to solve this problem. Here's a step-by-step solution:

1. Define the Regular Expression (regex):

   import re
   regex = r'Part 1\.(.*?)Part 3'

   This regex specifies that we're looking for "Part 1" followed by any number of characters (represented by ".*?") before the string "Part 3."

2. Create a Pattern Object:

   pattern = re.compile(regex)

3. Perform the Pattern Match:

   match_obj = pattern.search(string)

4. Retrieve the Matched Text:

   if match_obj:
       matched_text = match_obj.group(1)

   The "group(1)" method extracts the text captured within the parentheses in the regex.

Example Usage:

Given the string "Part 1. Part 2. Part 3 then more text," the output of the code would be:

matched_text = '. Part 2. '

Alternative Approach:

If there are multiple occurrences of the pattern, you can use the "re.findall" function instead of "re.search" to obtain a list of all matches.

match_list = re.findall(r'Part 1\.(.*?)Part 3', string)

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