Re: strange map behavior

Perl sometimes guesses a block is an anonymous hash constructor and vice-versa.

my %h = map {; $_ => $_ } @arr;
             ^
             |
       force a block.
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my @a = map +{ $_ => ord($_) }, @arr;
            ^
            |
      force a hash
[download]

By the way, why are you using "$_" instead of just $_?

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Re^2: strange map behavior by jeanluca (Deacon) on Feb 25, 2008 at 19:24 UTC
I tried to build a new hash out of an array with hashes, something like: `#! /usr/bin/perl -l use strict; use warnings ; my @arr = ( {'a' => 'x', 'b' => 'y', 'c' => 'z'}, {'a' => 'x1', 'b' => 'y1', 'c' => 'z1'} ) ; my %h = map {;"$_->{'a'}_$_->{'c'}" => $_->{'b'} } @arr ; print "$_ -- $h{$_}" foreach ( keys %h ) ;` [download] Thnx LuCa	[reply] [d/l]
Re^3: strange map behavior by ikegami (Patriarch) on Feb 25, 2008 at 19:33 UTC
That makes more sense. But you might want to use `join` to increase readability. `my %h = map { join('_', $_->{'a'}, $_->{'c'}) => $_->{'b'} } @arr ;` [download]	[reply] [d/l] [select]