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How do I combine arrays and array of hashes?

by bradcathey (Prior)
on Dec 31, 2008 at 02:23 UTC ( [id://733384]=perlquestion: print w/replies, xml ) Need Help??

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

Perl uses a little magic to combine arrays, but the more complex reference to an AoH requires a bit more magic

ARRAYS:

my @aoh1 = qw (value1 value2); my @aoh2 = qw (value3 value4); @aoh2 = (@aoh1, @aoh2);

output:

@aoh2 = ('value1', 'value2', 'value3', 'value4' );

AoH's:

@aoh1 = ({ 'key1' => 'value1', 'key2' => 'value2' }); @aoh2 = ({ 'key3' => 'value3', 'key4' => 'value4' }); @aoh2 = (@aoh1, @aoh2);

output:

@aoh2 = ( { 'key2' => 'value2', 'key1' => 'value1' }, { 'key4' => 'value4', 'key3' => 'value3' } );

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Re: How do I combine arrays and array of hashes?
by fullermd (Priest) on Dec 31, 2008 at 06:46 UTC

    The question isn't quite clear as to the desired outcome. I'll read it as: you want to turn two one-element arrays, each of whose element is a hashref, into one one-element array, whose element is a hashref of the combined hashes. That seems a little weird.

    But here's one idea:

    @aoh2 = ({map { %$_ } (@aoh1, @aoh2)});

    It does the same thing with multiples; e.g., if one of the arrays has multiple hashrefs in it, it still gets rolled up into one output:

    @aoh1 = ({ 'key1' => 'value1', 'key2' => 'value2' }); @aoh2 = ({ 'key3' => 'value3', 'key4' => 'value4' }, { 'key5' => 'value5', 'key6' => 'value6' }); @aoh2 = ({map { %$_ } (@aoh1, @aoh2)});
    Output:
    @aoh2 = ( { 'key5' => 'value5', 'key2' => 'value2', 'key6' => 'value6', 'key4' => 'value4', 'key1' => 'value1', 'key3' => 'value3' } );
      As fullermd notes, the OP's question is a bit unclear. If the intent was to combine arrays of hashes and produce a simple array (an operation not subject to problems with conflicting keys), fullermd's solution can be modified to:
      @aoh3 = map {values %$_} (@aoh1, @aoh2);

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