Beefy Boxes and Bandwidth Generously Provided by pair Networks
Perl-Sensitive Sunglasses
 
PerlMonks  

Answer: undef vs. $foo = 0

( #163548=categorized answer: print w/ replies, xml ) Need Help??

Q&A > input and output > undef vs. $foo = 0 contributed by ariels

One sets the variable to undef, the other to 0. They're not equivalent. "Resetting" a variable is probably more like undef $bar.

But which you want probably depends on what it is you want to do. For some applications, you'd set $bar=0 initially (or $bar='' for others), so that could be useful.

Example

To print the sum of the numbers in an array,
my $sum; # ... $sum = 0; $sum += $_ for @array; print "Sum is $sum\n";
Using undef $sum would be a somewhat subtle error in this case.

Other times, you want undefinedness, and you undef things accordingly. Which is right to use depends on what is "right".

Log In?
Username:
Password:

What's my password?
Create A New User
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others scrutinizing the Monastery: (11)
As of 2016-06-26 11:18 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?
    My preferred method of making French fries (chips) is in a ...











    Results (328 votes). Check out past polls.