regex - 如何修复正则表达式以匹配整个单词，而不是子字符串？

Question

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Answer 1

正则表达式:

\bBaby\b

测试here .

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要同时找到“Baby”和“Blay”，您需要将正则表达式更新为:

\b(Baby|Blay)\b

测试here .

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解释:

来自 here关于\b:

The metacharacter \b is an anchor like the caret and the dollar sign. It matches at a position that is called a “word boundary”. This match is zero-length.

There are three different positions that qualify as word boundaries:

• Before the first character in the string, if the first character is a word character.
• After the last character in the string, if the last character is a word character.
• Between two characters in the string, where one is a word character and the other is not a word character.

Simply put: \b allows you to perform a “whole words only” search using a regular expression in the form of \bword\b. A “word character” is a character that can be used to form words. All characters that are not “word characters” are “non-word characters”.

来自 here关于 (Baby|Blay) :

If you want to search for the literal text cat or dog, separate both options with a vertical bar or pipe symbol: cat|dog. If you want more options, simply expand the list: cat|dog|mouse|fish.

The alternation operator has the lowest precedence of all regex operators. That is, it tells the regex engine to match either everything to the left of the vertical bar, or everything to the right of the vertical bar. If you want to limit the reach of the alternation, you need to use parentheses for grouping. If we want to improve the first example to match whole words only, we would need to use \b(cat|dog)\b. This tells the regex engine to find a word boundary, then either cat or dog, and then another word boundary. If we had omitted the parentheses then the regex engine would have searched for a word boundary followed by cat, or, dog followed by a word boundary.