Hi
I have following re
$Test="5-15";
my (@sid)= ($Test=~/(\d+)-(\d+)/?($1..$2):$_);
which polulate the @sid with 5 to 15 numbers,
what I don't understand is
?($1..$2):$_) how does this work
Please do not ask thousands of people to read the documentation for you.
From
perldoc perlop:
Conditional Operator
Ternary "?:" is the conditional operator, just as in C. It works much
like an if-then-else. If the argument before the ? is true, the
argument before the : is returned, otherwise the argument after the :
is returned.
Now, I personally would hope that I would never write anything like
this. Assuming $_ supposedly holds some default value, I would re-write
this as:
#! perl
use strict;
use warnings;
my $default = 1;
my $test = '5-15';
my @range;
if($test =~ /^(\d+)-(\d+)$/) {
@range = ($1 .. $2);
} else {
@range = ($default);
}
print "@range\n";
__END__
I don't know where the $test string is coming from, but you probably
want to perform some additional bounds checking on the variables. What
happens to your program if $test contains:
'0-2000000000'
Sinan
