On Tuesday, 19 May 2015 at 14:31:21 UTC, Ivan Kazmenko wrote:
On Tuesday, 19 May 2015 at 10:00:33 UTC, BlackEdder wrote:
The documentation seems to indicate that partialShuffle:
Partially shuffles the elements of r such that upon returning
r[0..n] is a random subset of r, (which is what I want), but
it seems that partialShuffle actually only shuffles the first
subset of the range (which you could do probably also do by
[0..n].randomShuffle).
This different behaviour was problem created since:
https://issues.dlang.org/show_bug.cgi?id=11738. Does anyone
know what the intended behaviour is/was?
Reading the current documentation and unittests, I now also
believe the fix was a mistake. Reopened the issue for now with
a comment: https://issues.dlang.org/show_bug.cgi?id=11738#c2
I hope Joseph Rushton Wakeling looks into it soon.
Reading the documentation it does appear that the function
behaviour is at odds with what is described. I don't know how I
came to that misunderstanding.
In the short term, if you want a randomly-shuffled random subset
of a range, you could get it via something like,
original_range.randomSample(n).array.randomShuffle;
or maybe better
original_range.randomShuffle.randomSample(n);
