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NchooseK
DescriptionRandomly chooses an array of k entries from the array 0 .. (n-1). (n entries beginning with 0)
Syntax
NchooseK($n, $k)Params
$n-- the length of the original array
$k-- the length of the sub array
Returns
A subarray of length k with entries between 0 and (n-1)
Examples
To obtain 3 random letters from the first five letters of the alphabet.@slice = NchooseK(5,3)# @slice might be (1, 0, 3)
@random_letters = A..Z[@slice]
# @random_letters will now contain the subarray (B, A, D) taken from the array (A, B, C, D, E, ..... Z)
#(Remember that perl arrays begin indexing with zero.)
A fancy way to obtain a permuation of an array:@permuted_array = @array[ NchooseK($#array, $#array) ]
Notes
Defined in PGchoicemacros.pl
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