Re: Selecting particular key-value pairs in hashes

in reply to Selecting particular key-value pairs in hashes

Non-destructively:

  my %hash2 = map  {$_ => $hash{$_}}
              grep {/^\d+_\d+$/}
              keys %hash;
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Comment on Re: Selecting particular key-value pairs in hashes Download Code

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Re^2: Selecting particular key-value pairs in hashes by Aristotle (Chancellor) on Sep 18, 2004 at 20:34 UTC
You can pick more than one value at a time out of a hash — see merlyn's code and gaal's remark. `my %hash2 = @hash{ grep /\d+_\d+/, keys %hash };` [download] Update: thanks to bobf for notifying me that this code makes, uh, very little sense. Here's a hash slice incantation that actually works: `my %hash2; @hash2{ @$_ } = @hash{ @$_ } for [ grep /\d+_\d+/, keys %hash ]; # or more verbosely my %hash2; { my @key = grep /\d+_\d+/, keys %hash; @hash2{ @key } = @hash{ @key }; }` [download] Makeshifts last the longest.	[reply] [d/l] [select]

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Re^2: Selecting particular key-value pairs in hashes
by Aristotle (Chancellor) on Sep 18, 2004 at 20:34 UTC

You can pick more than one value at a time out of a hash — see merlyn's code and gaal's remark.

my %hash2 = @hash{ grep /\d+_\d+/, keys %hash };
[download]

Update: thanks to bobf for notifying me that this code makes, uh, very little sense. Here's a hash slice incantation that actually works:

my %hash2;
@hash2{ @$_ } = @hash{ @$_ } for [ grep /\d+_\d+/, keys %hash ];

# or more verbosely

my %hash2;
{
    my @key = grep /\d+_\d+/, keys %hash;
    @hash2{ @key } = @hash{ @key };
}
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Makeshifts last the longest.

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