How to Extract Substrings Enclosed by Markers in Python?

Extracting Substrings Enclosed by Markers in Python

In many programming scenarios, it becomes necessary to extract specific parts of a string based on predefined markers or delimiters. Let's consider an example where we want to retrieve the '1234' substring from the string 'gfgfdAAA1234ZZZuijjk'.

To address this requirement effectively, import the 're' module, which provides powerful regular expression capabilities in Python. Here are the steps involved:

1. Define a regular expression pattern using the 're.search' function:

   m = re.search('AAA(.+?)ZZZ', text)

   • 'AAA' and 'ZZZ' represent the markers enclosing the desired substring.
   • '. ?' matches any non-greedy sequence of characters between the markers.

2. Check if the pattern matches in the given text:

   if m:
       found = m.group(1)

   • If the pattern matches successfully, 'm' will be a Match object.
   • Use 'm.group(1)' to extract the captured substring enclosed between the markers.

Alternatively, you can simplify the code using a try-except block:

try:
    found = re.search('AAA(.+?)ZZZ', text).group(1)
except AttributeError:
    # Handle the case when markers are not present in the string
    found = ''

In both cases, the result will be assigned to the 'found' variable, which will contain the '1234' substring.

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