Beefy Boxes and Bandwidth Generously Provided by pair Networks
Clear questions and runnable code
get the best and fastest answer

Re: How come undef eq '' ??

by tmharish (Friar)
on Jan 30, 2013 at 15:45 UTC ( #1016087=note: print w/replies, xml ) Need Help??

in reply to How come undef eq '' ??

Not to get into a discussion on what perl should do but:

perl -e 'if( $tmp eq 0 ) { print "In\n" } else { print "Out\n" }' Out

By the same logic - I cant seem to understand why this is not true! Especially considering undef $a; $a++ works as expected.

Replies are listed 'Best First'.
Re^2: How come undef eq '' ??
by muba (Priest) on Jan 30, 2013 at 15:55 UTC

    Because eq is for string comparisons. undef stringifies to "", 0 stringifies to "0", and "" ne "0".

    Change eq to == and it will print "In".

Re^2: How come undef eq '' ??
by Corion (Pope) on Jan 30, 2013 at 15:53 UTC

    eq is for string comparison. ++ is a numeric operator. Maybe that's where the root of the preceived discrepancy lies?

Re^2: How come undef eq '' ??
by tmharish (Friar) on Jan 30, 2013 at 16:53 UTC

    Corion, muba ... Yup, with the 0 I should have used == and it would have been consistent with eq and ''.


Log In?

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://1016087]
and all is quiet...

How do I use this? | Other CB clients
Other Users?
Others making s'mores by the fire in the courtyard of the Monastery: (5)
As of 2018-01-18 22:46 GMT
Find Nodes?
    Voting Booth?
    How did you see in the new year?

    Results (215 votes). Check out past polls.