RE: Regex help

[asmith9983]

Hi

Unless Perl is the only tool available to you in your toolbox and if you're 
running Linux or similar consider the "tr -s " command in a shell. However if 
you are 
strictly limited to Perl then this stand regex works:-
echo ",,,,,"|perl -ane 's/,*/,/;print'
Try it by cutting and pasting it.
No doubt you'll get lots of other answers,so choose the one you like best,and 
can remember.

--
Andrew in Edinburgh,Scotland

On Mon, 3 Sep 2007, Andrew Curry wrote:

Christ That's certainly 1 way ;)

-----Original Message-----
From: John W. Krahn [mailto:[EMAIL PROTECTED]
Sent: 03 September 2007 16:11
To: Perl beginners
Subject: Re: Regex help

Beginner wrote:
Hi,

Hello,

I am trying to come up with a regex to squash multiple commas into
one. The line I am working on looks like this:

SPEED OF LIGHT, ,  LIGHT SPEED,TRAVEL,TRAVELLING, ,
DANGER,DANGEROUS,PHYSICAL, ,  CONCEPT,CONCEPTS, , , , , , , , , ,

There are instances of /,\s{1,},/ and /,,/

The bit that I am struggling with is finding a way to get a use a
multiplier for the regex /,\s+/ but I have to be careful not to remove
single entries. I guess the order of my substitutions is important
here.

$ perl -le'
$_ = q[SPEED OF LIGHT, ,  LIGHT SPEED,TRAVEL,TRAVELLING, ,
DANGER,DANGEROUS,PHYSICAL, ,  CONCEPT,CONCEPTS, , , , , , , , , , ];  >
print; s/,\s*(?=,)//g; print; '
SPEED OF LIGHT, ,  LIGHT SPEED,TRAVEL,TRAVELLING, ,
DANGER,DANGEROUS,PHYSICAL, ,  CONCEPT,CONCEPTS, , , , , , , , , , SPEED OF
LIGHT,  LIGHT SPEED,TRAVEL,TRAVELLING,  DANGER,DANGEROUS,PHYSICAL,
CONCEPT,CONCEPTS,


$ perl -le'
$_ = q[SPEED OF LIGHT, ,  LIGHT SPEED,TRAVEL,TRAVELLING, ,
DANGER,DANGEROUS,PHYSICAL, ,  CONCEPT,CONCEPTS, , , , , , , , , , ]; print;
$_ = join ",", grep /\S/, split /,/; print; '
SPEED OF LIGHT, ,  LIGHT SPEED,TRAVEL,TRAVELLING, ,
DANGER,DANGEROUS,PHYSICAL, ,  CONCEPT,CONCEPTS, , , , , , , , , , SPEED OF
LIGHT,  LIGHT SPEED,TRAVEL,TRAVELLING,  DANGER,DANGEROUS,PHYSICAL,
CONCEPT,CONCEPTS




John
--
Perl isn't a toolbox, but a small machine shop where you can special-order
certain sorts of tools at low cost and
in short order.                            -- Larry Wall

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