http://www.perlmonks.org?node_id=36572

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question: ⭐ (files)

How else can I read from a file without using a while loop, testing for the EOF?

Originally posted as a Categorized Question.

  • Comment on How else can I read from a file without using a while loop, testing for the EOF?

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Re: How else can I read from a file without using a while loop, testing for the EOF?⭐
by S@nto (Initiate) on Apr 23, 2006 at 17:53 UTC
    Much less dangerous than undef-ing $/ globably (and maybe forgetting to set it back) local-ize it to a block that just does your file reading:
    my $string = do{ local $/; <$filehandle> };

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    Or you can use $RS if you can't (or don't want to) remember $/.
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      I like the slurp method provided by IO::All: 
      use IO::All;

my @lines = io('file.txt')->slurp;

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Re: How else can I read from a file without using a while loop, testing for the EOF?⭐
by Fastolfe (Vicar) on Oct 13, 2000 at 22:05 UTC
    A while (<FH>) { ... } block implicitely tests for eof. Are you trying to avoid the <FH> construct (which reads line-by-line, unless you've undefined $/ as mentioned by another poster), such as with binary files?

    There are also the very standard and documented built-ins: read and sysread. These will read an arbitrary amount of data from a file.

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Re: How else can I read from a file without using a while loop, testing for the EOF?
by ickiller (Novice) on Oct 13, 2000 at 20:38 UTC
    As i know, the most efficient method is to set the input record separator to nothing like the following snippet: 

    $/ = undef;
$wholefile = <FILE>;

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    Roli
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Re: How else can I read from a file without using a while loop, testing for the EOF?
by japhy (Canon) on Oct 13, 2000 at 16:56 UTC
    I wish you'd use a description... what's with the "no while loop" idea? I mean, you can do: 
    @lines = <FILE>;

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    but that's potentially silly and memory-hogging.

    Originally posted as a Categorized Answer.

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Re: How else can I read from a file without using a while loop, testing for the EOF?
by t0j0 (Novice) on Oct 14, 2000 at 05:22 UTC
    or maybe you can use file-slurp function.. 
    use File::Slurp;

# to get your data into scalar variable
$output_string = read_file($filename);

# or this to get your data into array
@output_array = read_file($filename);

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Re: How else can I read from a file without using a while loop, testing for the EOF?
by tye (Sage) on Oct 14, 2000 at 08:56 UTC

    Oh, but the looping and checking for EOF is the trivial part. I hate the open()ing, checking for [and properly reporting] failure, and close()ing part. 

    my @lines;
{ local( @ARGV )= $filename;
  @lines= <>;
}

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        - tye

    Originally posted as a Categorized Answer.

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