And lexicographically means...

...make sure you sprintf numbers with %0xxd, where the xx is enough space for the widest number in that column, and make sure you format strings with %-yys where yy is enough space for the widest string in that column.

That way, the fields will "cmp" correctly.

If you need keys sorted in a different order, just sprintf them differently. For descending numeric keys, sprintf 9999999-$fld. For descending string keys... Hmmm, don't have an easy answer to that one. Of course, as long as you don't need some string keys desc and others asc, you can just reverse the order of the cmp call in the sort block.

Hope this helps!
--
Mike

Comment on And lexicographically means...

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Re: And lexicographically means... by Juerd (Abbot) on Mar 16, 2002 at 18:17 UTC
If you need keys sorted in a different order, just sprintf them differently. For descending numeric keys, sprintf 9999999-$fld. For descending string keys... Hmmm, don't have an easy answer to that one. `# Ascending sort { $a cmp $b } LIST sort { $a <=> $b } LIST # Descending sort { $b cmp $a } LIST sort { $b <=> $a } LIST` [download] I think using 9999999-$foo is an ugly way to do a descending sort, and I think sprintfing to sort numbers using cmp is evil, because there's already the <=> operator and you can use every routine you want for sorting - just reverse it if you want a descending sort. U28geW91IGNhbiBhbGwgcm90MTMgY W5kIHBhY2soKS4gQnV0IGRvIHlvdS ByZWNvZ25pc2UgQmFzZTY0IHdoZW4 geW91IHNlZSBpdD8gIC0tIEp1ZXJk	[reply] [d/l]
It's an efficiency thing, not an elegance thing by RMGir (Prior) on Mar 16, 2002 at 19:41 UTC
I'm building up the string key using sprintf just to avoid perl code in the comparison function. Evil yes. But also EFFICIENT. I'll bet for a long sort, it's probably faster to do a cmp than several cmps and <=>. But it's the weekend; I'm too lazy to fire up Benchmark. :) -- Mike	[reply]
Re: And lexicographically means... by I0 (Priest) on Mar 16, 2002 at 18:46 UTC
For descending string keys sprintf ~$fld	[reply]