Validating field to contain only numbers separated by commas

I'm making a form validation callback in code igniter. I'm trying to validate an input that needs to be numbers separated by commas, no spaces. For example

开发者_如何学JAVA

1,2,3,4,5 221,78,4,82,991,12 10001,10010,20010 etc

Whats the best way to validate this regex? Some other PHP wizardry?

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Why not a regex like this?

/^(\d+,)*\d+$/

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Here's an expression that won't require any backtracking.

/^(?:\d+(?:,|$))+$/

The non-capturing groups (?:regex) also make it faster.