CODEWITHSUNDEEP
c#regex
soandos
soandos

Reputation: 5146

Match many regexes on the same string at once

I have a number of regular expressions that attempt to find items in a very long (~100 pages of text) string, with each looking for a particular thing (i.e. one looks for one type of information, another looks for a different type, etc).

Each regex group will have ~50 matches or so in the text, but it takes a while to run them all in sequence.

Is there a way that I can run all the of regular expressions on a string at once, or otherwise create a regular expression where the capture groups can occur in any order (any number of times)?

Upvotes: 1

Views: 84

Answers (2)

Tim Pietzcker
Tim Pietzcker

Reputation: 336128

You can put all the single regexes into a large regex using groups and alternation:

bigregex = "(?:" + regex1 + "|" + regex2 + "|" + regex3 + ")"

However, this will only give you the desired result if the matches of each regex can never overlap, and if you're not using numbered capturing groups with backreferences.

Upvotes: 2

Matthew Vines
Matthew Vines

Reputation: 27561

This is probably not exactly what you need, but may spark an idea. I use this as a single pass, multi-token, find and replace.

public static string MultiReplace(this string target, Dictionary<string, string> replacementDictionary)
    {
                    return Regex.Replace(target, "(" + String.Join("|", replacementDictionary.Keys.ToArray()) + ")", match => replacementDictionary[match.Value]);
    }

Upvotes: 0

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