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);
A call to map doesn't modify the object list - it simply returns the modified
list, and in this case you're simply throwing that result away. Take a look at
perldoc -q "grep in a void context"
as the same comments apply to map.
You need to do either
@_ = map { defined $_ ? $_ : 'str' } @_ ;
or
do {$_ = 'str' unless defined } for @x;
or you could just print the return value of map directly:
print map { defined $_ ? $_ : 'str' } @_ ;
HTH,
Rob
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