Printing Integer with thousands separator?

[miblo]

This ought to be simple, but I just can't figure it out:

How do I print a large integer with thousands separators? I.e. I want a large integer (for example 65674564376548) to be printed as 65,674,564,376,548.

I'm sure a regexp can do it. The example below works, but it starts from the left, and thus doesn't produce what I want...

$n = 65674564376548;
$n =~ s/([0-9]{3})/$1 /g;

Any tips appreciated.
~Mike

 

[DumTech]

There's an example exactly like this in the llama book. I'm not in a position to look it up or even test what's below, but it's something along these lines...

$n = 123456789;
1 while $n =~ s/(\d+)(\d\d\d)/$1,$2/;

Or something like that. As you can see it takes as many digits as it can up until the last three, then inserts a comma...$1 = 123456 $2 = 789 and you get 123456,789
Can't match past the comma next time around, so you get $1=123 $2=456 and wind up with 123,456,789. Can't match enough digits next time through so the "do-nothing" loop exits.

Perl experts? I just read this chapter last night, and of course, I've slept since then...
But Mike, that's the general idea!

 

[goBoating]

#!/usr/local/bin/perl
$n = '9876543210';
$n = reverse($n);
$n =~ s/(\d\d\d)/$1,/g;
$n = reverse($n);
print "$n\n";
If you are new to Tek-Tips, please use descriptive titles, check the FAQs,
and beware the evil typo.

 

[goBoating]

DumbTech is on the right track,

from Jeffrey Friedl's "Mastering Regular Expressions",
paraphrased to make it operate on '$n',

#!/usr/local/bin/perl
$n = '9876543210';
print"$n\n";
1 while ($n =~ s/^(-?\d+)(\d{3})/$1,$2/);
print"$n\n";

HTH If you are new to Tek-Tips, please use descriptive titles, check the FAQs,
and beware the evil typo.

 

[miblo]

Thanks for all your tips - I now have it working as I wanted.

~Mike