CODEWITHSUNDEEP
pythonpython-3.xregexword-boundary
Sakurai
Sakurai

Reputation: 106

Word boundary between ASCII and Unicode letters in Python3

Python3:

import re
k = "X"
s = "X测试一Q测试二XQ测试三"
print(re.split((r"\b" + k + r"\b"), s))

Output:

['X测试一Q测试二XQ测试三']

Expected:

['', '测试一Q测试二XQ测试三']

Upvotes: 1

Views: 120

Answers (1)

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 626929

The 测 is a letter belonging to the \p{Lo} class and there is no word boundary between X and 测.

A \b word boundary construct is Unicode-aware by default in Python 3.x re patterns, so you might switch this behavior off by using the re.ASCII / re.A option, or the inline (?a) flag:

import re
k = "X"
print( re.split(fr"(?a)\b{k}\b", "X测试一Q测试二XQ测试三") )

See the regex demo and the Python demo.

If you need to make sure there is no ASCII letter before and after X, use (?<![a-zA-Z])X(?![a-zA-Z]). Or, including digits, (?<![a-zA-Z0-9])X(?![a-zA-Z0-9]).

Upvotes: 1

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