how to split hash into two arrays

baxy77bax has asked for the wisdom of the Perl Monks concerning the following question:

hi,

i need a quick oneliner for this script if one exists:


my $array->[0] = $arg{key1};
my $key->[0] = 'key1' if ($array->[0]);
[download]

so basically i have a hash that needs to be broken into two arrays and depending on a hash key the position of the key and value needs to be placed on a specific position in two corresponding arrays

thank you

Update:

ok i have a sub() that takes some variables. and the way to pass some variables to that sub is through hash interface.like this:


sub _sub {

my %arg = @_;

my $array;    # sometimes is treated as a scalar
$array->[0] = $arg{key1};
$array->[1] = $arg{key2};
$array->[2] = $arg{key3};
$array->[3] = $arg{key4};
...
}
[download]

sometimes user can pass only one variable to the _sub(). for example

_sub(key3 => 'big-mama');
[download]

in this case only the $array->[2] will be defined and all others will be undef. so what i need is one extra array that will tell me the key (key3) that corresponds to that variable and that key should be placed on a $secarray->[2] position

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Re: how to split hash into two arrays by Your Mother (Archbishop) on Jul 07, 2009 at 08:00 UTC
Possibly (sorry, not one liner)- `use YAML; my ( @one, @two ); my %one_two = map {; $_ => int(rand(2) } 1 .. 10; for my $key ( keys %one_two ) { push @one, $key; push @two, $one_two{$key} \|\| undef; # "skips" 0s here. } print Dump ( \%one_two, \@one, \@two );` [download]	[reply] [d/l]
Re: how to split hash into two arrays by missingthepoint (Friar) on Jul 07, 2009 at 08:04 UTC
Your post is a little dense and also slightly confusing. This is the best I can do, but I'd like you to clarify what you want. In particular, what do you mean by depending on a hash key the position of the key and value needs to be placed on a specific position in two corresponding arrays? `# assume %h is your hash, @c and @d are the 'corresponding arrays' @keys=keys %h;@vals=values %h;for($i=0;$i<@keys;$i++){$c[9] = $d[9] = +$i if $keys[$i] eq 'something'}` [download] I'm assuming: By 'depending on a hash key' you mean 'if one particular key exists in the hash' You know the 'specific position' (ie offset) in the other two arrays in which you want to place the offset of the particular key/value (in the code I've used `9` arbitrarily) The zeroeth step in writing a module is to make sure that there isn't already a decent one in CPAN. (-- Pod::Simple::Subclassing)	[reply] [d/l] [select]
Re: how to split hash into two arrays by Anonymous Monk on Jul 07, 2009 at 08:00 UTC
i need a quick oneliner for this script if one exists Happy? `my $array->[0] = $arg{key1};my $key->[0] = 'key1' if ($array->[0]);` [download] :D	[reply] [d/l]
Re: how to split hash into two arrays by grizzley (Chaplain) on Jul 07, 2009 at 11:42 UTC
I think you don't need any extra array. Just the sub you already have. If some param is not passed, null will be assigned to `$array->[x]`: `C:\>perl -le "use strict;use warnings;sub f{my($x,$y)=@_;my $aa=$x;my +$bb=$y; print $aa, ' ', $bb}; f(1); f(2,3)" Use of uninitialized value $bb in print at -e line 1. 1 2 3` [download] This means, that in first case $bb equals 'undef' as you want.	[reply] [d/l] [select]


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