Re^3: skipping the first line of a file

my ... for ...; is not valid Perl.

Well, it seems to compile and run with no warnings or errors.

use strict;
use warnings;

my $discard = <DATA> for 1 .. 2;
print while <DATA>;

__END__
Header 1
Header 2
Data 1
Data 2
Data 3
[download]

$ ./spw770971
Data 1
Data 2
Data 3
$
[download]

Please could you explain in what way it is not valid.

Cheers,

JohnGG

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Re^4: skipping the first line of a file by ikegami (Patriarch) on Jun 13, 2009 at 20:11 UTC
Because the docs says it isn't. The behaviour of a my statement modified with a statement modifier conditional or loop construct (e.g. `my $x if ...` ) is undefined. The value of the `my` variable may be `undef`, any previously assigned value, or possibly anything else. Don't rely on it. Future versions of perl might do something different from the version of perl you try it out on. Here be dragons. ( ~~Emphasis~~Strong emphasis in original. ) That said, the current behaviour is actually quite predictable, and it doesn't limit `$discard` to the loop `>perl -cwe"use strict; my $x for 1..2; print $x" -e syntax OK` [download] So not only is not valid Perl, it doesn't even work.	[reply] [d/l] [select]
Re^5: skipping the first line of a file by johngg (Canon) on Jun 13, 2009 at 22:28 UTC
You learn something new every day. I'll remember not to do that in future but use a real loop instead. Thank you, JohnGG	[reply]


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