in reply to Golf, anyone? :)
in thread disappearing digit with regex and tr

perl -e '$_=1234567;s/\./,/;s/(?=(\d\d\d)+(,|\Z))/./g;print'

That doesn't handle 234567 nor 234567.89 too well. :)

My best, based on yours, obviously:

y/./,/;s/\d(?=(\d\d\d)+(,|\Z))/$&./g; # 37, counting the semicolon

Update: Ow, too obviously. \Z is just long-hand for $ ... so slice one off ... and update2 \d\d\d can be shortened to \d{3} for one more:

y/./,/;s/\d(?=(\d{3})+(,|$))/$&./g; # 35, counting the semicolon
... or, to demonstrate ...
sidhekin@blackbox:~$ perl -le 'for (@ARGV) { y/./,/;s/\d(?=(\d{3})+(,| +$))/$&./g;print }' 1234567.89 234567.89 1234567 234567 1.234.567,89 234.567,89 1.234.567 234.567 sidhekin@blackbox:~$

print "Just another Perl ${\(trickster and hacker)},"
The Sidhekin proves Sidhe did it!

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Re^2: Golf, anyone? :)
by suaveant (Parson) on Aug 18, 2006 at 18:02 UTC
    Ooops. Just needs a little positive lookbehind.

    perl -le 'for(@ARGV){s/\./,/;s/(?<=\d)(?=(\d\d\d)+(,|\Z))/./g;print}' +1234567.89 234567.89 1234567 234567 1.234.567,89 234.567,89 1.234.567 234.567

    update..

    Ok.. yours is shorter... mine is probably more efficient for not invoking $& at least :)

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