Re^3: Little annoying mistakes ... of others

[szabgab]

Wow, I am writing down the examples as test cases but I can't figure out why is the second example always true?

could you please explain?

[jeffa]

I think this:

print "$arg matches\n" if grep $arg, @valid;

Is equivalent to this:

print "$arg matches\n" if grep { $arg } @valid;

So as long as @valid and $arg are not false, then the match will also be true. (If $arg is 0 (zero) then the second example will not always be true.)