A comment on the regexen:

# regex to add a comma after each char
# i believe you can think of it starting
# at the second character since
# ?<= means look to the left of the current
# position
# the . means to look at one character
# the () are required to capture each character
$show_choices =~ s/(?<=.)/,/g;
$show_choices =~ s/,$//g;       # remove the last comma

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Actually, there is no capturing being done in the first regex; the parentheses are there only for grouping, i.e. to show where the positive look-behind assertion ends. (Try adding a $1 to the replacement part, and you will get a series of error messages beginning Use of uninitialized value $1.)

The first regex could also be written as:

$show_choices =~ s/(.)/$1,/g;

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which does capture each character.

The two regexen can be combined into one using a negative look-ahead assertion:

$show_choices =~ s/(.)(?!$)/$1,/g;

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See “Look-Around Assertions” under Extended Patterns in perlre.

Hope that helps,

Athanasius <°(((>< contra mundum Iustus alius egestas vitae, eros Piratica,

In reply to Re: Perl replacement for choice.com by Athanasius
in thread Perl replacement for choice.com by onelander

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