Problem with using file handle in hash

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

Hi, I am having problem with using a file handle in a hash. For example:

###############################
my %FileHandles;
my $Dir = '/tmp';
my $FileName = 'test';
open $FileHandles{$Dir}{$FileName}, "$Dir/$FileName" or die "Cannot op
+en $Dir/$FileName: $!";

while (<$FileHandles{$Dir}{$FileName}>) {
    print $_;
}

$FileHandles{$Dir}{$FileName}->close;
###############################
[download]

The script above doesnt' print the contents in the test file. I only get a line like "GLOB(0xdfa4440)" instead. Any idea?

Comment on Problem with using file handle in hash Download Code

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Re: Problem with using file handle in hash by GrandFather (Saint) on Jun 24, 2016 at 04:29 UTC
`while (<$FileHandles{$Dir}{$FileName}>)` doesn't work. You must use a simple variable. The fix is: `... my $fh = $FileHandles{$Dir}{$FileName}; while (<$fh>) { print $_; }` [download] Premature optimization is the root of all job security	[reply] [d/l] [select]
Re^2: Problem with using file handle in hash by sophate (Beadle) on Jun 24, 2016 at 05:16 UTC
thanks for the prompt reply. Simple variable works!	[reply]
Re: Problem with using file handle in hash by BrowserUk (Patriarch) on Jun 24, 2016 at 05:06 UTC
The diamond operator doesn't like compound variables; but you can work around that by using its function form: readline. This works fine: `while( readline( $Some{compound}{variable}[1] ) ) { ... }` [download] With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". I knew I was on the right track :) In the absence of evidence, opinion is indistinguishable from prejudice. Not understood.	[reply] [d/l]
Re^2: Problem with using file handle in hash by stevieb (Canon) on Jun 24, 2016 at 11:00 UTC
I ran into this a few months ago as I wanted to create a dictionary of handles, but somehow, never came across `readline`. I'm glad this thread came up.	[reply] [d/l]
Re^2: Problem with using file handle in hash by sophate (Beadle) on Jun 24, 2016 at 05:17 UTC
thanks. this can work around it too!	[reply]