CODEWITHSUNDEEP
javascriptregex
Arkadiusz Kałkus
Arkadiusz Kałkus

Reputation: 18403

How can I negate part of a class in a regular expression?

I want to negate part of a class in a regular expression. Let's say we have an expression accepting repeated big or small letters from a to z.

[a-zA-Z]+

How can I negate for example H letter?

I've tried this [a-zA-Z^H]+ but it doesn't block H.

I know we can do it otherwise, but I search for a general rule to negate inside of a class.

I use JavaScript flavor of regex.

UPDATE

Here's the more specific example. Here's the expression: [\w\-\–]. In .NET flavor it accepts unicode characters, but in JavaScript flavor it doesn't. There's a trick however to allow the expression to accept unicode chars too, \w must be replaced with this expression ([^\x00-\x7F]|\w).

The problem is - it can't be nested inside first expression ([\w\-\–]). That's why I'm asking how to make a negation of a part of a class.

Upvotes: 1

Views: 86

Answers (2)

anubhava
anubhava

Reputation: 785471

Translating my comment into an answer. Here is a regex that you can use for negating certain character or range:

/((?:[^\x00-\x7F]|[-\w–])+)/

RegEx Demo

Upvotes: 1

Jakub Konecki
Jakub Konecki

Reputation: 46008

Normally you would use class subtraction

[a-zA-Z--[H]]

For engines that don't support character class subtraction (javascript) you can simply use a negative lookahead.

((?![H])[a-zA-Z])+

Working example: https://regex101.com/r/sE6tH0/6

http://www.rexegg.com/regex-class-operations.html#subtraction_workaround

Upvotes: 1

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