Does Python's `re` Module Correctly Handle Word Boundaries (`\b`) in Regular Expressions?

Do Regular Expressions from the re Module Support Word Boundaries (b)?

While attempting to use the b escape sequence to match word boundaries in Python's re module, inconsistencies may arise. The following code snippet demonstrates this:

>>> x = 'one two three'
>>> y = re.search("\btwo\b", x)

Surprisingly, the expected match object is absent, returning None instead. This raises the question of whether Python supports the b expression or if its usage is incorrect.

The discrepancy stems from the use of regular strings in the code. Raw strings should be employed instead, as demonstrated below:

>>> x = 'one two three'
>>> y = re.search(r"\btwo\b", x)

This modification resolves the issue, yielding a match object as intended.

Additionally, consider using the following approach:

word = 'two'
re.compile(r'\b%s\b' % word, re.I)

This ensures case-insensitive matching, potentially expanding the scope of successful matches.

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