Re: Argument isn't numeric in sort -- resolve or ignore?

[davido]

Forget about those two lines for a moment. Why would your comparator return $a, or $b, or -1, 0, 1? The first and final returns will return the result of N <=> M, whereas all the other returns return the value being compared instead. That's got to be a bug.

[stevieb]

A bug where, sir? In perl, or in the OPs code? I'm legitimately interested in any details/feedback you can provide.

[GrandFather]

In the OP's code. The return $a lines will return values like 'etc'. Sort expects -1, 0 or 1 as is returned by cmp and <=>.

[davido]

GrandFather did a better job of explaining it than I did.

sort expects the comparator subroutine to return a value less than zero, equal to zero, or greater than zero for the conditions of left < right, left == right, and left > right. So the use of cmp and <=> is commonplace. But some of the possible return values of the OP's comparator are strings, which will probably not be of much use to sort. It seems as though the OP thinks he should return the value that has higher precedence in the comparison, which is a fallacy, and except for unusual circumstances, indicative of a bug in the code.

[Argel]

Yeah, it's been probably more than five years since I had to write my own sort routine and faulty memory did me in. It doesn't help that all but three of the sites in my actual data have numbers in them and most are all numbers, so it appeared to be working. Thanks for the help!!