splitting contents of a variable ( not what you think!! )

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

Hi.. I've got a short Perl question... I want to take the contents of a variable called, say, $input

$input = "word+word+word";
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and split it up, so that i can put something along the lines of the following into a variable, which we'll call $string

keyword1=word&keyword2=word&keyword3=word
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I've drawn up some mock Perl code to help give a better idea of what i mean.

$string = "";
$wordnum = 0;
$input = "word+word+word";
(@keywords) = split(/\+/, $input);

foreach $keyword (@keywords){
$wordnum++;
$string .= qq~keyword_$wordnum=$keyword~;
}
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Re: splitting contents of a variable ( not what you think!! ) by blakem (Monsignor) on Jan 28, 2002 at 04:49 UTC
How about using the powers of `join`, `map` and `split`? `#!/usr/bin/perl -wT use strict; my $input = "word+word+word"; my $i=1; my $string = join '&', map {"keyword".$i++."=$_"} split /\+/, $input; print "$string\n"; __END__ keyword1=word&keyword2=word&keyword3=word` [download] Reading that complicated line from bottom to top... First we `split` the string into pieces, then we `map` those pieces to the new format, finally we `join` them together with a new delimiter. Update: Just for kicks... this regex seems to work as well: `my $i = ''; (my $string = $input) =~ s/(^\|\+)/($i++&&'&')."keyword$i="/ge;` [download] -Blake	[reply] [d/l] [select]
Re: splitting contents of a variable ( not what you think!! ) by Masem (Monsignor) on Jan 28, 2002 at 04:51 UTC
You're close. You probably want to put all your strings into an array, then use the reverse of split, join to put your '&' into place. Continuing from your code: `my @strings; foreach $keyword (@keywords){ $wordnum++; push @strings, "keyword_$wordnum=$keyword"; } my $string = join '&', @strings;` [download] ----------------------------------------------------- Dr. Michael K. Neylon - mneylon-pm@masemware.com \|\| "You've left the lens cap of your mind on again, Pinky" - The Brain "I can see my house from here!" It's not what you know, but knowing how to find it if you don't know that's important	[reply] [d/l]
Re: splitting contents of a variable ( not what you think!! ) by Juerd (Abbot) on Jan 28, 2002 at 11:13 UTC
`my $input = 'foo+bar+baz'; my $i = 1; my $string = join '&', map { 'keyword' . $i++ . '=' . $_ } split /\+/, + $input;` [download] This might be the first time you see map. It's not as hard as it looks: `map BLOCK LIST` evaluates BLOCK for every item of the given LIST, aliassing `$_` to that item. In other words: `map` creates a list out of a list. So this is what happens: `$input` gets split, and the individual items are sent through `map`, which prefixes "keyword#=", increasing the number by one. Then, `join` joins them using supergl^W'&'. The result is put in `$string`. `2;0 juerd@ouranos:~$ perl -e'undef christmas' Segmentation fault 2;139 juerd@ouranos:~$` [download]	[reply] [d/l] [select]