How Can I Find Overlapping Matches Using Python Regular Expressions?

Finding Overlapping Matches with Regular Expressions

In Python, using the re module, finding all overlapping matches of a pattern can be achieved through the use of a lookahead, which captures the desired matches while keeping the actual match technically non-overlapping.

Capturing Group Lookahead:

The key to capturing overlapping matches is to use a capturing group within a lookahead assertion. The lookahead captures the desired text, but the actual match is the zero-width substring before the lookahead. This allows for technically non-overlapping matches:

import re

s = "123456789123456789"
matches = re.finditer(r'(?=(\d{10}))', s)  # 10-digit number series
results = [int(match.group(1)) for match in matches]

print(results)  # [1234567891, 2345678912, 3456789123, ...]

In this example, the pattern (d{10}) matches 10-digit sequences, while the lookahead (?=) captures and asserts the presence of these matches. The matches are then converted to integers using int(match.group(1)).

This technique allows for efficient identification of all overlapping matches within a larger string.

The above is the detailed content of How Can I Find Overlapping Matches Using Python Regular Expressions?. For more information, please follow other related articles on the PHP Chinese website!