Finding the length of an array must be an unusual thing for Perl programs to do, because Perl doesn't have an operator for it. It does have the evil $#:
You may find the length of array @days by evaluating $#days, as in csh. However, this isn't the length of the array; it's the subscript of the last element, which is a different value since there is ordinarily a 0th element.
Huh? What does this mean? And is Perl really modelled after csh? Let's try to do something simple, see how many arguments were passed to our program:
#!/usr/bin/perl -w
print "\$\#ARGV is $#ARGV\n";
Now let's run it...
$#ARGV is -1
/tmp/ two arguments
$#ARGV is 1
Huh? -1? This must have been confusing to others too, because it's documented again in the docs for @ARGV
$#ARGV is generally the number of arguments minus one, because $ARGV[0] is the first argument, not the program's command name itself.
I realize the simple rule is 'the length of @array is $#array+1', but how dumb is that?

Update: a friend pointed out you can get length by evaluating @array in scalar context. Contexts are one of those horrible features in Perl that make me have to relearn the language every time I write a program. There's more than one way to do it but none of them are simple.
  2003-09-13 19:25 Z