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Re^2: perl array of hashes help

by Anonymous Monk
on May 02, 2012 at 05:24 UTC ( #968355=note: print w/ replies, xml ) Need Help??


in reply to Re: perl array of hashes help
in thread perl array of hashes help

Hi Trizen, Thanks for your help , the code is working fine, can you please explain the two codes, similar to first one when i tried like this grep { $_->{bill} =~ '1117'} @array dint worked.. so what does ~~ this mean could you please explain me clearly. regards Sridhar


Comment on Re^2: perl array of hashes help
Re^3: perl array of hashes help
by trizen (Friar) on May 02, 2012 at 12:20 UTC
    Hi Sridhar! Please take a look at the smart match operator. As you can see, 'item' ~~ \@array returns true if the 'item' exists inside the array passed as an array reference.

    Your code doesn't work because $_->{bill} is a reference to an array, so what you are actually trying is something like this: 'ARRAY(0x886b7f8)' =~ /1117/; (i.e.: return true if the left side contains the substring from the right side).

    Of course, if you're trying to match a substring inside an array, you can use: grep { qr/1117/ ~~ $_->{bill} } @array;
      Hi Trizen,

      I have one question regarding access of the perl hash key which is an array reference like below i have an hash

       my $all = {'text' => [                                      'HJ0039_x.pdf' , 'HJ0039' , 'HJ0039'                                      ]};

      To access the above elements i can use two ways like below

       print " $all->{text}[0] ;

      and

       print "${$all->{text}}[0]

      can you please explain me clearly what is the difference between the above two methods , without de-referencing the array how we are able to access the array elements

      Thanks

        Hello Ragilla,

        The code $all->{text}[0] is equivalent with $all->{text}->[0]. This implies an implicit dereference. Similar with $array_ref->[0].

        In the second code, ${$all->{text}}[0] is similar with $array[0], because $all->{text} is an ARRAY REF, and @{ARRAY_REF} is similar with @array, which can lead to ${ARRAY_REF}[index].

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