Perl hashes are not associative arraysassociation lists, though I can see how one might think that way if one comes from a Lisp background. Please take a careful look at perldata and perldsc for a better understanding of Perl hashes and how to work with them.

How did you set up @data_list? The code above would only print out a value if you had set up @data_list something like this:

my @data_list = ( { correct => 42 } );
[download]

Or maybe you did something like this: my %data_list =(correct=>42)? That does not set up a collection of data pairs even though the fat comma (=>) may make it seem that way. To iterate through the elements of %data_list using a for loop one would need to use keys and do something like this:

  foreach my $k (keys %data_list) {
     my $v = $data_list->{$k};
     print "The value for $k is $v\n";
  }
[download]

@data_list=(correct => 42) doesn't set up discrete pairs either. It merely sets up a flat array with alternating keys and values. To iterate through key value pairs for @data_list one would need to do something like this:

   for (my $i=0; $i < $#data_list; $i+=2) {
     my $k = $data_list[$i];
     my $v = $data_list[$i+1];
     print "The value for $k is $v\n";
  }
[download]

Note that in Perl, %data_list and @data_list are two entirely different variables. If the preceding discussion does not clarify things, I think you will need to post more code so we can see how @data_list and/or %data_list is set up.

Best, beth

Update - struck out "associative array" and replaced with "association list" - see Re^5: Associative array for explanation.

---

---

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! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, 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, summary, 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:
	&		&
	<		&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.