random-access range whose elements are to be shuffled
number of elements of r to shuffle (counting from the beginning); must be less than r.length
The shuffled random-access range.
auto rnd = MinstdRand0(42); auto arr = [1, 2, 3, 4, 5, 6]; arr = arr.dup.partialShuffle(1, rnd); version (D_LP64) // https://issues.dlang.org/show_bug.cgi?id=15147 assert(arr == [2, 1, 3, 4, 5, 6]); // 1<->2 arr = arr.dup.partialShuffle(2, rnd); version (D_LP64) // https://issues.dlang.org/show_bug.cgi?id=15147 assert(arr == [1, 4, 3, 2, 5, 6]); // 1<->2, 2<->4 arr = arr.dup.partialShuffle(3, rnd); version (D_LP64) // https://issues.dlang.org/show_bug.cgi?id=15147 assert(arr == [5, 4, 6, 2, 1, 3]); // 1<->5, 2<->4, 3<->6
Partially shuffles the elements of r such that upon returning r[0 .. n] is a random subset of r and is randomly ordered. r[n .. r.length] will contain the elements not in r[0 .. n]. These will be in an undefined order, but will not be random in the sense that their order after partialShuffle returns will not be independent of their order before partialShuffle was called.
r must be a random-access range with length. n must be less than or equal to r.length. If no RNG is specified, rndGen will be used.