Retrieving an anonymous hash

paulgobble has asked for the wisdom of the Perl Monks concerning the following question:

Dear Wise Ones,

I've written a bit of code that opens a tab delimited text file, parses it, and stuffs it into an array of anonymous hashes. This works fine.

And while I can access any single value form any hash in the array with

$arrayOfHashes[$i]]{$key}

I'm having trouble plucking one of those anonymous hashes from the array and putting it into its own hash. The following bit of code does not work

my %tempHash = $arrayOfHashes[0] ;
my @tempKeys = keys %tempHash ;
[download]

nor does

my @keys= keys @arrayOfHashes[$i]

I get the error: Reference found where even-sized list expected

Whats the trick to plucking one entire hash from an array so that I can store it in its own hash or use hash functions (such as keys on it?

- Paul

Comment on Retrieving an anonymous hash Select or Download Code

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Re: Retrieving an anonymous hash by Limbic~Region (Chancellor) on Mar 18, 2004 at 18:27 UTC
Paul, I believe your issue is dereferencing. You should look at tye's References Quick Reference in tutorials. `my %hash = %{ $AoH[0] }; my @keys = keys %{ $AoH[3] };` [download] Cheers - L~R	[reply] [d/l]
Re: Retrieving an anonymous hash by TomDLux (Vicar) on Mar 18, 2004 at 18:43 UTC
I wonder whether you really want to move it to it's own hash. That involves making a copy of the anonymous hash in the AoH. I would suggest what you want is to assign ( to a scalar or to some other object ) a referencec to the anonymous hash, so you can manipulate it without involving a lengthy addressing procedure: `my $hashRef = $arrayOfHashes[0]; my @hashKeys = keys %$hashRef; # or more realistically ... for my $key ( keys %$hashRef ) { something involving $hashRef->{$key}; }` [download] -- `TTTATCGGTCGTTATATAGATGTTTGCA`	[reply] [d/l]
Re: Retrieving an anonymous hash by NetWallah (Canon) on Mar 18, 2004 at 20:07 UTC
Following up on what TomDLux said, another way of not copying the hash is to use type globs. `#Turn OFF use strict local *tempHash = $arrayOfHashes[0] ; # Now you can access $tempHash{whatever}` [download] Offense, like beauty, is in the eye of the beholder, and a fantasy. By guaranteeing freedom of expression, the First Amendment also guarntees offense.	[reply] [d/l]
Re: Re: Retrieving an anonymous hash by BUU (Prior) on Mar 18, 2004 at 23:22 UTC
#Turn OFF use strict Manipulating typeglobs is perfectly legal under strict, it's trying to treat strings as typeglobs thats illegal.	[reply]
Re: Re: Re: Retrieving an anonymous hash by NetWallah (Canon) on Mar 19, 2004 at 17:36 UTC
Actually you need to turn OFF strict when you USE the local variable, otherwise, you get `Global symbol "$x" requires explicit package name at blah ...` [download] To minimize exposure, it should be coded thus: `no strict qw(vars); ## Accessing code here ... use strict qw(vars);` [download] Offense, like beauty, is in the eye of the beholder, and a fantasy. By guaranteeing freedom of expression, the First Amendment also guarntees offense.	[reply] [d/l] [select]