Re: extracting elements by key from an array of hashes

If the keys are distinct over the hashes, the question is why to store them in an array.

my %hash = ( k0 => 'c0',
             k1 => 'v1',
             k2 => 'v2',
             k3 => 'v3',
           );
my $search = 'k2';
my $val = $hash{$search};
[download]

Even if the keys aren't unique, you might want to store the data in a HoA instead:

my %hash = ( k0 => ['c0'],
             k1 => ['v1'],
             k2 => ['v2', 'v42'],
             k3 => ['v3'],
           );
my $search = 'k2';
my @vals = @{ $hash{$search} };
[download]

لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ

Comment on Re: extracting elements by key from an array of hashes Select or Download Code

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Re^2: extracting elements by key from an array of hashes by ciderpunx (Vicar) on Sep 25, 2015 at 10:06 UTC
True that. However, the data is coming from an xmlrpc source via XML::RPC and that's how it's structured. I don't have control over the source API or at least I don't want to change it. -- Charlie Harvey.	[reply]
Re^3: extracting elements by key from an array of hashes by choroba (Cardinal) on Sep 25, 2015 at 10:35 UTC
You can easily create a temporary hash to do the searches: `my %hash = map %$_, @rpc;` [download] لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ	[reply] [d/l]
Re^3: extracting elements by key from an array of hashes by davido (Cardinal) on Sep 25, 2015 at 14:57 UTC
Keep in mind that you have no obligation to store data internally in inconvenient formats. If it is more convenient to manipulate it internally as a hash, do that conversion at the earliest possible point after reading it in, and convert back at the latest possible point if you ever have to output the structure again. Dave	[reply]
Re^3: extracting elements by key from an array of hashes by Anonymous Monk on Sep 25, 2015 at 10:45 UTC
... and if there is potentially more than one value per bucket, simply make each element an arrayref. Auto-vivification makes this trivially easy to do.	[reply]