regular expressions

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Brandon McCombs - 09 Jan 2006 01:34 GMT

hello,

The java doc on Sun's site is useless for figuring out how to do a
split() on a string and to split on either a ( or a ). I noticed that I
have to use \p{Punct} but the page says nothing on how to do that. Can
anyone help me? I've created a Pattern object and think I have to
compile the pattern but I have no damn clue what the pattern is supposed
to be with the stupid \p argument that I have to use just to split on a
( or ). I don't know why they can't be used as commas because with
commas I don't have to do anything special to make the split work.

thanks

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hiwa - 09 Jan 2006 02:17 GMT

( and ) should be escaped as \\( and \\)
Read the API documentation of java.util.regex.Pattern class.

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Brandon McCombs - 09 Jan 2006 03:09 GMT

> ( and ) should be escaped as \\( and \\)
> Read the API documentation of java.util.regex.Pattern class.

The proper escaping was what I needed. I found it hard to believe I had
to go to the trouble of making a pattern object. I was only escaping
with 1 backslash when I had tried it previously.
thanks

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hiwa - 09 Jan 2006 03:51 GMT

In a Java string, you need to write two backslashes.

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Roedy Green - 09 Jan 2006 04:33 GMT

>( or ). I don't know why they can't be used as commas because with
>commas I don't have to do anything special to make the split work.

See http://mindprod.com/jgloss/regex.html
You want a pattern that is either ( or ).

You have likely seen pattern of the form [01]
to allow either 0 or 1.

Do the same thing with ( and )

namely [()]

However, () have magic meaning in Regexes, so you quote them to tell
Java you mean them literally, not as command characters.

namely "[\(\)]"

The problem with that is Java also uses \ for quoting in strings. So
to let Java know you meant those \ literally you must double them.

namely "[\\(\\)]"

That's your pattern for the split.

Signature

Canadian Mind Products, Roedy Green.
http://mindprod.com Java custom programming, consulting and coaching.

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ricky.clarkson@gmail.com - 13 Jan 2006 02:08 GMT

Roedy,

I refer people in another medium to your regex page when we get
questions where the answer is a double-escape, with the following text:

"http://mindprod.com/jgloss/regex.html#VARIANTS - see the first text
under the Function heading."

Could you possibly make that part less table-based, or provide another
page just for the 'double escape' part? Something I can give a less
vague link to.

Regards.

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Roedy Green - 13 Jan 2006 03:33 GMT

On 12 Jan 2006 18:08:06 -0800, "ricky.clarkson@gmail.com"
<ricky.clarkson@gmail.com> wrote, quoted or indirectly quoted someone
who said :

>Could you possibly make that part less table-based, or provide another
>page just for the 'double escape' part? Something I can give a less
>vague link to.

done. Should show up on the website in a few minutes.

Signature

Canadian Mind Products, Roedy Green.
http://mindprod.com Java custom programming, consulting and coaching.

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ricky.clarkson@gmail.com - 13 Jan 2006 10:50 GMT

Excellent stuff, thanks a lot.

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regular expressions

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