Re: Localizing hash keys in an AoH

Can you not just localise the entire AoH?:

{ 
    local @data; 
    $data[ $_ ]{unit} = 'something' for 0 .. $#data; 
    ... 
} 
# all changes undone here
[download]

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Comment on Re: Localizing hash keys in an AoH Download Code

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Re^2: Localizing hash keys in an AoH by NetWallah (Canon) on Mar 15, 2013 at 20:48 UTC
That would probably require: `local @data = @data;` [download] else local @data would initialize empty. (At least it does, in my tests). Suffers from "Can't localize lexical variable @data at ..." Update: this works: `LOCAL_BLOCK_5: { local @data[0..$#data]; $_->{unit} = 'S' for @data; print Dumper \@data; }` [download] Update 2: Just noticed kennethks solution below, that changes @data to a package (our) variable, and allows it to be localized. "I'm fairly sure if they took porn off the Internet, there'd only be one website left, and it'd be called 'Bring Back the Porn!'" -- Dr. Cox, Scrubs	[reply] [d/l] [select]
Re^3: Localizing hash keys in an AoH by kennethk (Abbot) on Mar 15, 2013 at 22:18 UTC
Localizing the array slice seems to work, which is weird because localizing the array did not -- see Re^2: Localizing hash keys in an AoH. Huh. Regardless, thank you! Just what the doctor ordered. #11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.	[reply]
Re^4: Localizing hash keys in an AoH by NetWallah (Canon) on Mar 16, 2013 at 03:11 UTC
Looks like you can do all that in a single line as well: `perl -E 'use strict;my @x=map {Z=>$_+999}, 0..5;{$_->{Z}=33 for local + @x[0..$#x]; say $x[2]{Z}}; say $x[2]{Z}' 33 1001` [download] "I'm fairly sure if they took porn off the Internet, there'd only be one website left, and it'd be called 'Bring Back the Porn!'" -- Dr. Cox, Scrubs	[reply] [d/l]
Re^2: Localizing hash keys in an AoH by kennethk (Abbot) on Mar 15, 2013 at 20:58 UTC
When you localize the array, it's only the array elements that get localized; you still have the original hash refs. `#!/usr/bin/perl use strict; use warnings; use Data::Dumper; our @data = ( {unit => 'S', value => 50, }, {unit => 'T', value => 60, }, {unit => 'Q', value => 70, }, ); LOCAL_BLOCK: { local(@data) = @data; $_->{unit} = 'S' for @data; } print Dumper \@data;` [download] outputs `$VAR1 = [ { 'unit' => 'S', 'value' => 50 }, { 'unit' => 'S', 'value' => 60 }, { 'unit' => 'S', 'value' => 70 } ];` [download] #11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.	[reply] [d/l] [select]