CODEWITHSUNDEEP
c#regex
olf
olf

Reputation: 872

Regex MatchCollection gets too many results

Using C# and Regex I have a strange situation:

string substr = "9074552545,9075420530,9075662235,9075662236,9075952311,9076246645";
MatchCollection collection = Regex.Matches(substr, @"[\d]*");

In my world the above would give me a result in 'collection' that contains 6 results. Strangly enough my collection contains 12 results and every second result is {} (empty).

I have tried rewriting it to:

string substr = "9074552545,9075420530,9075662235,9075662236,9075952311,9076246645";
Regex regex = new Regex(@"[\d]*");
MatchCollection collection = regex.Matches(substr);

But it gives me the exact same result. What am I missing here?

I am using .Net framework 4.5, C#

Upvotes: 6

Views: 322

Answers (2)

Ahmed KRAIEM
Ahmed KRAIEM

Reputation: 10427

There is no need for regex:

string[] results = substr.Split(',');

Upvotes: 1

p.s.w.g
p.s.w.g

Reputation: 149108

I believe the problem is your * quantifier. It matches zero or more characters, which means an empty string is technically a match. You need to use the + quantifier, like this:

string substr = "9074552545,9075420530,9075662235,9075662236,9075952311,9076246645";
MatchCollection collection = Regex.Matches(substr, @"\d+");

// or
Regex regex = new Regex(@"\d+");
MatchCollection collection = regex.Matches(substr);

It will ensure that only strings with one or more digits are returned.

Note, I've also dropped the character class ([]) around your \d as it's completely unnecessary here.

Further Reading:

Upvotes: 7

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