Weide wrote:
Can anyone tell me why the map will not map out the unitialized
variable in this code with 'str'? Thanks a lot,
use strict;
use warnings;
sub total
{
my $firstone = shift;
my $sum = 0;
my $item = 0;
map { defined $_ ? $_ : 'str' } @_ ;
print @_;
}
my $hello;
print "not defined there\n" unless defined $hello;
my @data1 =('a','b','c','d',$hello);
total(@data1);
Some options:
print map { defined $_ ? $_ : 'str' } @_ ;
@_ = map { defined $_ ? $_ : 'str' } @_ ;
map { $_ = 'str' unless defined } @_ ;
But people will tell you that using map in void context
(option 3) is wrong.
Your mistake was thinking that map sets $_ to the return
value of the block. Instead, you must set $_ inside the
block if that's what you want.
--
Brad
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