if the number is 7 digits longs it doesnt add the comma

The reason is because you anchor your match to the end of the line with $. Your regex is doing exactly what you're asking it to do: match 4 digits at the end of the string, and insert a comma in the appropriate place.

It's messy to write a "normal" regex to do what you want, because regular expressions scan your string from left to right. The easiest way commafy a number is to actually reverse the string first, as demonstrated by borisz's earlier post.

In reply to Re: simple regex by revdiablo
in thread simple regex by Anonymous Monk

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