A regular expression that only matches nothing?

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steve.chambers@gmail.com - 08 May 2006 16:41 GMT

Can such a thing be done?

To explain myself a bit better I need a regular expression that will
only match an empty string ("") - if there is any text in the string I
don't want it to match. Won't go into why, it would take too much
explanation!

Thanks for any help/suggestions...

Cheers,
Steve

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Eric Sosman - 08 May 2006 16:55 GMT

steve.chambers@gmail.com wrote On 05/08/06 11:41,:

> Can such a thing be done?
>
> To explain myself a bit better I need a regular expression that will
> only match an empty string ("") - if there is any text in the string I
> don't want it to match. Won't go into why, it would take too much
> explanation!

Pattern empty = Pattern.compile("^$");

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Eric.Sosman@sun.com

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Jeffrey Schwab - 09 May 2006 22:39 GMT

> I need a regular expression that will
> only match an empty string ("") - if there is any text in the string I
> don't want it to match. Won't go into why, it would take too much
> explanation!

.{0}

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steve.chambers@gmail.com - 16 May 2006 11:21 GMT

Both seem to work, not sure which is best but will probably go with the
.{0} suggestion as its meaning seems slightly more intuitive.

Thanks v. much to both of you for the helpful suggestions.

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A regular expression that only matches nothing?

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