in reply to Re: Check if array is null
in thread Check if array is null

Your first and second are identical in function:


our @array2;
my @array3;
my @array4 = ();
my @array5 = (undef);
my @array6 = ('one');

print("defined:\n");
print('array1: ', defined(@array1)?1:0, "\n");  # 0
print('array2: ', defined(@array2)?1:0, "\n");  # 0
print('array3: ', defined(@array3)?1:0, "\n");  # 0
print('array4: ', defined(@array4)?1:0, "\n");  # 0
print('array5: ', defined(@array5)?1:0, "\n");  # 1
print('array6: ', defined(@array6)?1:0, "\n");  # 1
print("\n");

print("explicit scalar:\n");
print('array1: ', scalar(@array1)?1:0, "\n");   # 0
print('array2: ', scalar(@array2)?1:0, "\n");   # 0
print('array3: ', scalar(@array3)?1:0, "\n");   # 0
print('array4: ', scalar(@array4)?1:0, "\n");   # 0
print('array5: ', scalar(@array5)?1:0, "\n");   # 1
print('array6: ', scalar(@array6)?1:0, "\n");   # 1
print("\n");

print("implicit scalar:\n");
print('array1: ', @array1?1:0, "\n");           # 0
print('array2: ', @array2?1:0, "\n");           # 0
print('array3: ', @array3?1:0, "\n");           # 0
print('array4: ', @array4?1:0, "\n");           # 0
print('array5: ', @array5?1:0, "\n");           # 1
print('array6: ', @array6?1:0, "\n");           # 1
print("\n");

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I don't think defined should be used on an array.

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Re^3: Check if array is null
by Limbic~Region (Chancellor) on Oct 06, 2004 at 16:41 UTC
    ikegami,
    Your first and second are identical in function

    Not according to my test: 

    #!/usr/bin/perl
use strict;
use warnings;
my @array = (undef, undef);
print "foo\n" if defined @array;
print "bar\n" if grep defined , @array;
__END__
$ perl foo.pl
defined(@array) is deprecated at foo.pl line 5.
        (Maybe you should just omit the defined()?)
foo

$ perl -v
This is perl, v5.8.5 built for cygwin-thread-multi-64int

    [download]

    Cheers - L~R

[reply]
[d/l]
      Read again. I said the first and second are the same, not the first and third. Your snippet even supports me because it says defined shouldn't be used on arrays.
[reply]
[d/l]
        ikegami,
        Ok - so I can't read ;-) I still get conflicting results: 
        #!/usr/bin/perl
use strict;
use warnings;
my @array = (undef, undef);
pop @array;
pop @array;
print "foo\n" if defined @array;
__END__
defined(@array) is deprecated at foo.pl line 7.
        (Maybe you should just omit the defined()?)
foo

        [download]

        Cheers - L~R

[reply]
[d/l]

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