Foreach in mulitple arrays

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

It has been a while since I needed to delve into perl scripting and I've run across a fairly simple problem, I expect, but cannot, in short work, find a simple solution.

I have multiple arrays (that for other reasons need to remain seperate) that I would like to run the same foreach loop on. I realize that one solution would be to have the code be in a sub-routine and run each arrary through it.

However, I was wondering if it were possible to have something similar to foreach (@array1 @array2 @array3)

Thanks in advance,
magnus

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Re: Foreach in mulitple arrays by ikegami (Patriarch) on Jun 13, 2005 at 15:27 UTC
yes, you're only missing commas: `@array1 = qw( a b ); @array2 = qw( c d ); @array3 = qw( e f ); foreach (@array1, @array2, @array3) { print; } # output # ------ # abcdef` [download] If you wanted to go through them in parallel: `@array1 = qw( a b ); @array2 = qw( c d ); @array3 = qw( e f ); # Assumes all array are the same length. foreach (0..$#array1) { print($array1[$_], $array2[$_], $array3[$_], "\n"); } # output # ------ # ace # bdf` [download]	[reply] [d/l] [select]
Re^2: Foreach in mulitple arrays by magnus (Pilgrim) on Jun 13, 2005 at 15:37 UTC
Thank you both. It worked fine.	[reply]
Re: Foreach in mulitple arrays by BrowserUk (Patriarch) on Jun 13, 2005 at 15:26 UTC
Add 2 commas and that will work. Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal? "Science is about questioning the status quo. Questioning authority". The "good enough" maybe good enough for the now, and perfection maybe unobtainable, but that should not preclude us from striving for perfection, when time, circumstance or desire allow.	[reply] [d/l]
Re: Foreach in mulitple arrays by ambrus (Abbot) on Jun 13, 2005 at 18:17 UTC
Adding the commas indeed work. However, there's another, more general possibility too: factor the loop body out to a function and use three different foreach loops. Like, instead of `for (@array1, @array2, @array3) { print "met $_"; }` [download] you can write `my $body = sub { print "met $_"; } for (@array1) { &$body() } for (@array2) { &$body() } for (@array3) { &$body() }` [download] This works even if you have a more complicated iterator than foreach.	[reply] [d/l] [select]