Re: Sort hash ref of Hash of Hashes

[BioLion]

You are comparing string values 'PQRST' etc... but using the numerical sort (spaceship '<=>') operator. You should be using cmp. See sort for more info.

[moritz]

... and use warnings; would have warned you that Argument "PQRST" isn't numeric in numeric comparison (<=>) at ....

So, always use warnings;. (Documented in perllexwarn).