Anonymous Monk,
There are at least 3 easy ways to do this:

  • Assign the hash = to the return value of the sub: %hash = build_hash(sub {return %new_hash});
  • Pass a hash reference to the sub and return a reference $hashref = build_hash(sub {return \%new_hash});
  • Pass a hash reference to the sub and modify the original - see below

    The first is usually considered bad form as there is too much copying going on and it will not allow you to pass more than one hash at a time. The second is my preferred method, but it looks like you were going for number 3.

    #!/usr/bin/perl -w use strict; my %hash; build_hash(\%hash); print "$_ : $hash{$_}\n" foreach(keys %hash); sub build_hash { my $hash_ref = shift; $hash_ref->{'key1'} = "foo"; $hash_ref->{'key2'} = "bar"; }
    By the way, if you are going to loop over the hash to get both the keys and values, each is typically considered the way to go.

    Cheers - L~R


    In reply to Re: Preserving hash structure after subroutine call by Limbic~Region
    in thread Preserving hash structure after subroutine call by Anonymous Monk

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



    • Are you posting in the right place? Check out Where do I post X? to know for sure.
    • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
      <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
    • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
    • Want more info? How to link or or How to display code and escape characters are good places to start.