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What does the _ in [a-zA-Z0-9_] mean?

Tags:

regex

perl

What does the underscore mean in the following regex?

[a-zA-Z0-9_]

The _ seems to make no difference so I don't understand the purpose of it.

like image 490
unj2 Avatar asked Sep 05 '25 08:09

unj2

2 Answers

The underscore means an underscore.

like image 128
ndim Avatar answered Sep 08 '25 12:09

ndim

It means to match the underscore character in addition to lowercase letters, uppercase letters, and numbers.

like image 21
No Surprises Avatar answered Sep 08 '25 10:09

No Surprises
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