Beefy Boxes and Bandwidth Generously Provided by pair Networks
XP is just a number

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
I believe this is your question:
"I have an array (@data_list) containing hash references. Each hash reference contains two keys, 'key' and 'value'. I want to turn this into one hash containing 'key'=>'value' pairs. How can I do this?"

My solutions below assume that you have unique key values, or are un-interested in collisions. In the case of a collision, the last reference to the key wins.

Here is a fully verbose version:

my %final_hash; foreach my $data_pair ( @data_list) { $key = $data_pair->{ key }; $value = $data_pair->{value}; $final_hash{ $key } = $value; } use Data::Dumper; print Dumper \%final_hash;

A shorter version:

my %final_hash = map { $_->{key} => $_->{value} } @data_list; #verify the output use Data::Dumper; print Dumper \%final_hash;
And how do we know they work? We test them.

Full version with tests:

#!/usr/bin/perl -w use strict; use Data::Dumper; use Test::More tests => 2; my @data_list = ( { key => 'correct', value => 'AAA' }, { key => 'correction', value => 'BBB' }, { key => 'date', value => '20090303' }, { key => 'date', value => '20090308' }, ); my $expected = { correct => 'AAA', correction => 'BBB', date => '20090303', date => '20090308', }; my %final_hash_long; foreach my $data_pair (@data_list) { my $key = $data_pair->{key}; my $value = $data_pair->{value}; $final_hash_long{$key} = $value; } my %final_hash_short = map { $_->{key} => $_->{value} } @data_list; is_deeply( \%final_hash_long, $expected, "long version works" ); is_deeply( \%final_hash_short, $expected, "short version works" );

In reply to Re^3: Array to hash converstion by spazm
in thread Array to hash converstion by gem555

Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":

  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.
  • Log In?

    What's my password?
    Create A New User
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others taking refuge in the Monastery: (5)
    As of 2020-07-06 21:43 GMT
    Find Nodes?
      Voting Booth?

      No recent polls found