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Re: arrays from arrays

by fruiture (Curate)
on Mar 07, 2003 at 17:15 UTC ( #241189=note: print w/replies, xml ) Need Help??

in reply to arrays from arrays

So you say you have multiple values for certain keys.

key => value,value,value

This directly translates to Perl:

my %hash = ( key => [ value, value, value ], ... );

We call this a HoA, a hash of arrays as every value is another (anonymous) array-reference.

The creation of such a data structure is very easy with Perl as it has magic autovivification:

use Data::Dumper qw/Dumper/; my %hash = (); while( <DATA> ){ chomp; my ($k,$v) = split /\s*:\s*/; push @{ $hash{ $k } } , $v } print Dumper( \%hash ); __DATA__ green : apple yellow: banana green : kiwi red : strawberry green : mango yellow: lemon

That's it. Perl is great. update: see perlref and perldata of course.


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Re: Re: arrays from arrays
by Anonymous Monk on Mar 07, 2003 at 17:50 UTC

    Excellent, thanks for that, worked perfectly, even if I don't quite know how... will real up on Date::Dumper on Monday..


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[erix]: or compile & run an instance as yourself (not user 'postgres')
[erix]: easiest setup is to run with PG* env variables set, and a custom .pgpass files (can be a $PGPASSFILE)
[Corion]: Hmm - "trust" sounds interesting, but I have still to find whether I can restrict that on a per-DB level ;)
[Corion]: erix: Sure, but SQLite doesn't even need that :)
[hippo]: Corion: Yes, you can. It's all in the pg_hba.conf
[erix]: yeah, but there is a lot SQLite cannot do :)
[hippo]: Database is the 2nd column.
shmem .oO( docker. docker. docker? docker. docker! docker )
[shmem]: at least, some Ook.
[erix]: another simple Pg thing is to running a database off a tsv (alas, readonly)

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