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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.

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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 ''.


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