Re^4: Fastest way to lookup a point in a set

[swl]

There is also the issue of locales and the radix char when non-integer values are used with multidimensional hash keys.

If one has coordinates

[5,   5.5]
[5.5, 5  ]

then using the multidimensional hash approach in a locale where both $; and the radix char are a comma would result in ambiguous keys:

{5,5,5}
{5,5,5}

I know the original post specifies signed ints, so I'm just being more generic here. I also haven't checked if there is locale specific behaviour of $;

[LanX]

From the docs: The default subscript separator is "\034", the same as SUBSEP in awk

It's not "," , that's just the placeholder in Perl's syntax.

I don't know and can't think of any number format or localization which uses chr(28) .

Printable characters start from chr(32) onwards.

update

to avoid confusion

hex, oct, dez

perl -e "print 0x1c,034,28"
282828

[swl]

Thanks for clarifying.

Here are some more examples for those reading later and who haven't previously had to work with non-printing characters in this way (e.g. me a few hours ago):

#  default $; does not print
perl -e 'print join $;, 1..5'
12345

#  but $; is still in the string
perl -e '@x = split ($;, join ($;, 1..5)); print join ":", @x'
1:2:3:4:5

That still does leave the issue of debugging using print statements, as [5,55] and [55,5] will both print as 555 on a terminal. The point is effectively moot, though, as the other posts have shown multidimensional indexing is slower and should probably not be used in this case.