Regular question

frankus has asked for the wisdom of the Perl Monks concerning the following question:

Earlier today on the chatterbox someone asked how to seperate a number with numbers after each set of three digits.

i.e. 123456789 = 123,456,789

I really thought this was a cool use for Regular Expressions. The problem as I saw it required the regular expression to work on the result. I came up with this:

for(;;){s/^(\d+)(\d{3}($|,))(.*)/$1,$2,$4/;$2||last}
[download]

It seems to lack some of the grace I have come to expect from regular expressions. Anyone got an idea.

--

Brother Frankus.

Comment on Regular question Download Code

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Re: Regular question by Fastolfe (Vicar) on Nov 09, 2000 at 23:24 UTC
See How do I add commas to a number? in the Q&A section. Also see the perlfaq5 item: How can I output my numbers with commas added?	[reply]
RE: Regular question by Blue (Hermit) on Nov 09, 2000 at 23:34 UTC
Perhaps the best way would be to reverse the number and then add in commas every three, and reverse back, such as: `#!/usr/bin/perl -w use strict; sub commafy { my ($num)=@_; $num=reverse $num; $num=~s/(\d{3})(?=\d)/$1,/g; $num=reverse $num; } my $example = commafy(123456789); print "$example\n";` [download] Picked up that little trick here, and it's rather useful. =Blue ...you might be eaten by a grue... UPDATE: The links Fastolfe gave lead to more complete answers then mine, which only deals with integers.	[reply] [d/l]
Regular question errata. by frankus (Priest) on Nov 09, 2000 at 23:16 UTC
D'oh, it should be seperating a number with comments. And the exact question is: is there a regular expression suffix that makes the regex reprocess it's results? Apologies to all readers, it's late, my brain hurt, I go now. -- Brother Frankus.	[reply]