how to assign map results to arrays

perlfan99 has asked for the wisdom of the Perl Monks concerning the following question:

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Re: how to assign map results to arrays by ikegami (Patriarch) on Jul 29, 2008 at 06:53 UTC
You wouldn't have this problem if you were using `$var[n]` instead of `$varn`. `my @arrays = map { [ split /;/, $_ ] } @nums;` [download] But to answer your question: `my $num1 = "1;2;3"; my $num2 = "4;5;6"; my (@ar1, @ar2); for ( [ $num1, \@ar1 ], [ $num2, \@ar2 ], } { my ($num, $ar) = @$_; @$ar = split /;/, $num; }` [download] By the way, don't fool yourself into thinking the first argument of `split` is a text string. `split` expects a regexp.	[reply] [d/l] [select]
Re: how to assign map results to arrays by pc88mxer (Vicar) on Jul 29, 2008 at 06:51 UTC
How about: `@ar1 = split(';', $num1); @ar2 = split(';', $num2);` [download] Update: if you want to know how to get `# given: @num = ("1;2;3", "4;5;6"); $array[0] = [1, 2, 3]; $array[1] = [4, 5, 6];` [download] then you want: `@array = map { [ split(';', $_) ] } (@num);` [download] The square brackets around `split` create an array reference out of what `split` returns.	[reply] [d/l] [select]
Re: how to assign map results to arrays by GrandFather (Saint) on Jul 29, 2008 at 12:23 UTC
`(@ar1[0..2], @ar2[0..2]) = map { split(';', $_) } ($num1, $num2);` [download] Perl reduces RSI - it saves typing	[reply] [d/l]
Re: how to assign map results to arrays by perlfan99 (Sexton) on Jul 29, 2008 at 07:34 UTC
i like reference approach and it works, but i have to dereference it though, thanks for the tip `($ar1, $ar2) = map { [split(';', $_)] } ($num1, $num2);` not quite understand why dose Perl flatten the results.	[reply] [d/l]
Re^2: how to assign map results to arrays by davorg (Chancellor) on Jul 29, 2008 at 11:10 UTC
Perl flattens arrays. List assignment is greedy. The sooner you stop trying to fight it and just accept these fact, the happier your Perl programming experience will be :-) -- See the Copyright notice on my home node. "The first rule of Perl club is you do not talk about Perl club." -- Chip Salzenberg	[reply]
Re^2: how to assign map results to arrays by ikegami (Patriarch) on Jul 29, 2008 at 19:28 UTC
not quite understand why dose Perl flatten the results. Because Perl functions can only return one thing: a list of scalars. A list of scalars is created from the two arrays and returned by `map`. Then you ask to assign that list to a pair of arrays. There's no way for Perl to know how to split that list to assign it to two arrays, so it assigns the entire list to the first array.	[reply] [d/l]