is it the right reqular expression

i have following regular expression but it's not working properly it takes only three values after @ sign but i want it to be any number length

"/^[a-zA-Z0-9_\.\-]+\@([a-zA-Z0-9\-]+\.)+[a-zA-Z0-9]{2,4}$/"

this@开发者_如何学Pythonthi This is validated this@this It is not validating this expression

Can you please tell me what's the problem with the expression... Thanks

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If you want your regex to match "any number length" then why are you using {2,4}?

I think a better example of the strings you're trying to match might give others a better idea of what you want, because based on your regex it is a bit confusing what you're looking for.

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Try this:

^[a-zA-Z0-9_.-]+@([a-zA-Z0-9-]+\.)+[a-zA-Z0-9]{2,4}$

The main problem is that you didn't escape the dot: \.. In regular expression the dot matches everything (mostly), making your regex quite liberal.