BrowserUk:

Hmmm ... I can make it differently, but no cleaner, unfortunately:

$ cat 892828_a.pl
#!/usr/bin/perl
use strict;
use warnings;

my ($M, $N) = (9999997, 3);

my @ranges = map { $_ * int($M/$N) } 0 .. $N-1;
@ranges    = map { [ $ranges[$_], $ranges[$_+1]//$M ] } 0 .. $N-1;

print join(", ", map { "(".join("-",@{$_}).")" } @ranges), "\n";

$ perl 892828_a.pl
(0-3333332), (3333332-6666664), (6666664-9999997)

[download]

That one gets the second value wrong by one. I tried to find a way to stack the maps together, but couldn't figure out how to do it nicely.

This one gets the values right, but uses an uglier map statement, and still requires the "$ranges[-1][1]=$M" line, which I don't particularly care for:

$ cat 892828_b.pl
#!/usr/bin/perl
use strict;
use warnings;

my ($M, $N) = (9999997, 3);
my $step=0;
my @ranges = map { my ($c,$d)=($step,$_*int($M/$N)); $step=$d; [ $c, $
+d-1 ] } 1 .. $N;
$ranges[-1][1]=$M;
print join(", ", map { "(".join("-",@{$_}).")" } @ranges), "\n";

$ perl 892828_b.pl
(0-3333331), (3333332-6666663), (6666664-9999997)

[download]

Perhaps one of these will be close enough to inspire a better solution for you?

...roboticus

When your only tool is a hammer, all problems look like your thumb.

Update: Added code tags to a bit of text so it renders correctly.

In reply to Re: Split range 0 to M into N non-overlapping (roughly equal) ranges. by roboticus
in thread Split range 0 to M into N non-overlapping (roughly equal) ranges. by BrowserUk

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