CODEWITHSUNDEEP
regexstringactionscript-3variables
Olin Kirkland
Olin Kirkland

Reputation: 545

AS3 include a dynamic variable into a regexp object

How can I include a dynamic variable into a regexp object?

var pattern:RegExp = new RegExp(/'a '/ + keyword, '/gi');

In this case, I'd like the regex to match "a bird", or "A biRD" (if 'bird' is the keyword). However, 'bird' should not match if it is on its own.

Furthermore, I have a follow up question (I hope it's not too much to ask!): How would I do the exact thing above, but in which the regex only matches if the keyword is NOT preceded by 'a ' (I believe this involves the use of the ^ or the !, but I can't seem to find any clear documentation in any language for my specific request).

In the case of my second question test cases would look like this:

WORKS

abird
bird
bbbbirdddd

DOESN'T WORK

a bird
a birdddd

Any help will be greatly appreciated!

Upvotes: 4

Views: 1283

Answers (1)

Andrew Cheong
Andrew Cheong

Reputation: 30273

ActionScript 3.0 supports lookbehinds and the case-insensitive modifier:

/(?<=a\s+)bird/i

See here for more information on how to construct a regular expression from a variable: Using a Variable in an AS3, Regexp.

For the second part of your question:

/(?<!a\s+)bird/i

Upvotes: 1

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