regex101: 分组与断言

Pro

Group 1(\b\w+\b)

\ba Unicode word boundary

\w+a Unicode word character, repeated at least once

\ba Unicode word boundary

Group 2([ ]+\1\b)+

+repeats the group contents below at least once:

Character Class[ ]+

+matches at least one character from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

\1the text saved by group 1

\ba Unicode word boundary

Global pattern flags

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

s modifier: single line. Allows a dot to match line terminators

g modifier: global. Finds all matches instead of stopping after the first

25 tokens

Regular Expression

(\b\w+\b)([ ]+\1\b)+

New

the little cat cat is in the hat hat hat, we like it.
the little cat cat is in the hat hat hat, we like it.
the little cat cat is in the hat hat hat, we like it.
the little cat cat is in the hat hat hat, we like it.
the the little cat cat is in the hat hat hat, we like it.
the the the little cat cat2 is in the hat hat hat2, we like it.
aa abb bc
ab bbc cd dc dc dc eg

Substitution

\1

the little cat cat is in the hat hat hat, we like it.
the little cat cat is in the hat hat hat, we like it.
the little cat cat is in the hat hat hat, we like it.
the little cat cat is in the hat hat hat, we like it.
the the little cat cat is in the hat hat hat, we like it.
the the the little cat cat2 is in the hat hat hat2, we like it.
aa abb bc
ab bbc cd dc dc dc eg