comment on

I think I would do this using IO::File from the outset and would store information in a ref. to a HoH keyed by filename rather than in an array. I would start with a list of files to be processed in an array and would populate the hash with "handle" and "buffer" key/value pairs accessed via subroutines to keep it all in step. This way I have the advantage (if needed) to work with files both by name and by their index in a list of files.

In the script below I am reading four data files, spw592341.dataA to D, each containing a few lines that can easily be identified. Here's the script

use strict;
use warnings;

use Data::Dumper;
use IO::File;

print qq{Files to read\n};
my @dataFiles = glob q{spw592341.data*};
print qq{     $_\n} for @dataFiles;
print qq{\n};

my $rhFiles = {};

foreach my $file (@dataFiles)
{
    openFile($file);
    getLine($file);
}

showData(q{After reading first line});

foreach my $file (@dataFiles)
{
    getLine($file);
}

showData(q{All files read again});

getLine($dataFiles[2]);

showData(q{Read third file in list});

getLine(q{spw592341.dataD});

showData(q{Read spw592341.dataD});

foreach my $file (@dataFiles)
{
    closeFile($file);
}

showData(q{After closing all files});

sub closeFile
{
    my $file = shift;
    $rhFiles->{$file}->{handle}->close()
       or die qq{close: $file: $!\n};
    delete $rhFiles->{$file}->{handle};
}

sub getLine
{
    my $file = shift;
    $rhFiles->{$file}->{buffer}
       = $rhFiles->{$file}->{handle}->getline();
    chomp $rhFiles->{$file}->{buffer};
}

sub openFile
{
    my $file = shift;
    my $fh = IO::File->new($file, O_RDONLY)
       or die qq{open: $file: $!\n};
    $rhFiles->{$file}->{handle} = $fh;
}

sub showData
{
    my $msg = shift;
    print qq{\n$msg\n};
    my $dd = Data::Dumper->new(
       [$rhFiles], [qw{rhFiles}])->Indent(1);
    print $dd->Dumpxs();
}
[download]

The output is just Data::Dumper output of the hash ref. used to hold the data.

Files to read
     spw592341.dataA
     spw592341.dataB
     spw592341.dataC
     spw592341.dataD


After reading first line
$rhFiles = {
  'spw592341.dataB' => {
    'handle' => bless( \*Symbol::GEN1, 'IO::File' ),
    'buffer' => 'spw592341:dataB:line1'
  },
  'spw592341.dataD' => {
    'handle' => bless( \*Symbol::GEN3, 'IO::File' ),
    'buffer' => 'spw592341:dataD:line1'
  },
  'spw592341.dataA' => {
    'handle' => bless( \*Symbol::GEN0, 'IO::File' ),
    'buffer' => 'spw592341:dataA:line1'
  },
  'spw592341.dataC' => {
    'handle' => bless( \*Symbol::GEN2, 'IO::File' ),
    'buffer' => 'spw592341:dataC:line1'
  }
};

All files read again
$rhFiles = {
  'spw592341.dataB' => {
    'handle' => bless( \*Symbol::GEN1, 'IO::File' ),
    'buffer' => 'spw592341:dataB:line2'
  },
  'spw592341.dataD' => {
    'handle' => bless( \*Symbol::GEN3, 'IO::File' ),
    'buffer' => 'spw592341:dataD:line2'
  },
  'spw592341.dataA' => {
    'handle' => bless( \*Symbol::GEN0, 'IO::File' ),
    'buffer' => 'spw592341:dataA:line2'
  },
  'spw592341.dataC' => {
    'handle' => bless( \*Symbol::GEN2, 'IO::File' ),
    'buffer' => 'spw592341:dataC:line2'
  }
};

Read third file in list
$rhFiles = {
  'spw592341.dataB' => {
    'handle' => bless( \*Symbol::GEN1, 'IO::File' ),
    'buffer' => 'spw592341:dataB:line2'
  },
  'spw592341.dataD' => {
    'handle' => bless( \*Symbol::GEN3, 'IO::File' ),
    'buffer' => 'spw592341:dataD:line2'
  },
  'spw592341.dataA' => {
    'handle' => bless( \*Symbol::GEN0, 'IO::File' ),
    'buffer' => 'spw592341:dataA:line2'
  },
  'spw592341.dataC' => {
    'handle' => bless( \*Symbol::GEN2, 'IO::File' ),
    'buffer' => 'spw592341:dataC:line3'
  }
};

Read spw592341.dataD
$rhFiles = {
  'spw592341.dataB' => {
    'handle' => bless( \*Symbol::GEN1, 'IO::File' ),
    'buffer' => 'spw592341:dataB:line2'
  },
  'spw592341.dataD' => {
    'handle' => bless( \*Symbol::GEN3, 'IO::File' ),
    'buffer' => 'spw592341:dataD:line3'
  },
  'spw592341.dataA' => {
    'handle' => bless( \*Symbol::GEN0, 'IO::File' ),
    'buffer' => 'spw592341:dataA:line2'
  },
  'spw592341.dataC' => {
    'handle' => bless( \*Symbol::GEN2, 'IO::File' ),
    'buffer' => 'spw592341:dataC:line3'
  }
};

After closing all files
$rhFiles = {
  'spw592341.dataB' => {
    'buffer' => 'spw592341:dataB:line2'
  },
  'spw592341.dataD' => {
    'buffer' => 'spw592341:dataD:line3'
  },
  'spw592341.dataA' => {
    'buffer' => 'spw592341:dataA:line2'
  },
  'spw592341.dataC' => {
    'buffer' => 'spw592341:dataC:line3'
  }
};
[download]

I hope this is of use.

Cheers,

JohnGG

In reply to Re: Using a filehandle tucked into an array by johngg
in thread Using a filehandle tucked into an array by redbeard

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