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how to split hash into two arrays

by baxy77bax (Chaplain)
on Jul 07, 2009 at 07:49 UTC ( #777777=perlquestion: print w/ replies, xml ) Need Help??
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]);
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}; ... }
sometimes user can pass only one variable to the _sub(). for example
_sub(key3 => 'big-mama');
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 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]);
    :D
Re: how to split hash into two arrays
by Your Mother (Canon) 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 );
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'}

    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)
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
    This means, that in first case $bb equals 'undef' as you want.

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