Re^2: How to read data file into an array of hashes

Thanks guys. But now I come up with one more question. Now I want to print all the lines sorted by the Town. Like this

Town         Surname       Firstname

Basel        Chaplin       Charlie          
Manica       Estevez       Emilio Santa   
Montmarte    Sarte         Jean Paul  
Montmarte    Rodin         Paul 
Amsterdam    Rikard        Frank
[download]

I did something like this:

my $data = "clients.dat";
open (DAT, $data) or die "\"$data\" not existed or can't be opened!\n"
+;
my @client;  # make this an array, not a hash;
my @fields = qw/surname firstname town/;

while (<DAT>) {
    next if ( /^Surname/ or /^-/ );
    my @values = unpack 'A20A20A20', $_;
    my %entry = map { $fields[$_] => $values[$_] } ( 0..$#fields );
    push @client, \%entry;
}

my @towns;
my $client;
foreach my $client (@client){
    push @towns, "$client->{'town'}";
}
my @sorted_towns = sort @towns;

foreach my $key (@sorted_towns) {
    my @elems = $key;
    my $client = $client->[$elems[1]-1];
    print "$client->{'town'} $client->{'surname'} $client->{'firstname
+'}";
    
}
[download]

But this doesnt work somehow. Can anyone help please?

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Re^3: How to read data file into an array of hashes by graff (Chancellor) on Jun 24, 2009 at 18:02 UTC
You don't need (or want) to sort the town names into a separate array; after the AoH is loaded, you just need to loop over the list of sorted array elements, where the sorting is based on the "town" value, like this: `for my $entry ( sort { $a->{town} cmp $b->{town} } @client ) { printf "%s\t%s\t%s\n", $entry->{town}, $entry->{surname}, $entry-> +{firstname}; }` [download] (not tested) (updated to add missing "->" in the printf statement, based on fseng's reply below)	[reply] [d/l]
Re^4: How to read data file into an array of hashes by fseng (Novice) on Jun 25, 2009 at 06:00 UTC
Thanks graff.I tested the code. It keeps giving error message: Global symbol "%entry" requires explicit package name. I try to declare it as my %entry, then it gives error message: use of unintialized value in printf. I dont get it.	[reply]
Re^4: How to read data file into an array of hashes by fseng (Novice) on Jun 26, 2009 at 00:14 UTC
Hi it does work. I think I did some stupid thing but it works perfect now. Thanks a lot.	[reply]