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uninitialized value warning in reading file

by dannoura (Pilgrim)
on Jul 10, 2003 at 08:40 UTC ( [id://272916]=perlquestion: print w/replies, xml ) Need Help??

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

Hi,

This should be a simple one. Whenever I use code similar to:

#! c:\perl\bin
use strict;
use warnings;

open (FH, "somefile.txt") or die("cannot open file");
foreach (<FH>) {
print if ($_=~/foo/);
}

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I get a lot of uninitialized value warnings. I assume this is because there are empty lines at the end of the file, but I'm not sure and also even if this is the case I don't know how to get rid of the warnings (except for turning off use warnings).

Any ideas?

Replies are listed 'Best First'.
Re: uninitialized value warning in reading file
by ant9000 (Monk) on Jul 10, 2003 at 10:12 UTC
    Use this construct for looping
    while(defined($_=<FH>)){

    [download]
    and you should be fine.
[reply]
[d/l]
      Hi,

      as i understood it up to now there is no difference between (defined($_=<FH>)) and (<FH>).

      Have a look at man perlop, Page 33.

      Perhaps it could be useful if dannoura shows us an excerpt of his somefile.txt.

      greetings, tos

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Re: uninitialized value warning in reading file
by Anonymous Monk on Jul 10, 2003 at 10:21 UTC

    Not an alternative to better coding practice suggested by ant9000 but:

    #!/usr/bin/perl 
use strict;
use warnings;
no warnings qw(uninitialized); #turn off uninit warnings

    [download]
    See perldoc perllexwarn ...

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