CODEWITHSUNDEEP
regex
Mary
Mary

Reputation: 1145

How can I exclude a specific character combination from my regular expression?

For example, suppose I want to search for strings beginning with two capital letters:

[A-Z][A-Z]

but I want to exclude strings beginning with 'AB'. How do I incorporate the exclusion into my regular expression?

Upvotes: 2

Views: 2023

Answers (3)

summerrain
summerrain

Reputation: 227

(?!AB)[A-Z]{2}

explanation:
(?!AB): negative lookahead: excludes strings beginning with AB
[A-Z]{2}: matches 2 capital letters

Upvotes: 3

Jamie Howarth
Jamie Howarth

Reputation: 3323

[A-Z](?!B)[A-Z]

The (?!B) bit says "match any letter, but not if it's followed by B".

Upvotes: 0

rici
rici

Reputation: 241931

The direct solution:

([B-Z][A-Z]|A[AC-Z])

In other words, if it starts with a capital Ietter other than A, then any second capital will do, but if it starts with an A, the second letter cannot be B so it must be A or in the range C-Z.

Upvotes: 1

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