Combinations (n !
r): Generates a sequence of numeric integer vectors comprising all
combinations of n things taken r at a time. The ( !
)symbol is used because of the use of factorials in the math. This
operator is currently limited to about 200K of output.
Number of Combinations (n #!
r): Reports the number of combinations of n things taken
r at a time. The actual combinations are not produced. The glyph is
the combination of the pound ( # ) glyph commonly used for number of
items and the combination symbol ( ! ).
Permutations (n !!
r): Returns a sequence of numeric integer vectors containing all the
permutations of n things taken r at a time. The double
factorial ( !! ) symbol is used because it returns more results its
cousin, the combination. This operator is currently limited to about 200K of
output.
Number of Permutations (n #!!
r): Returns the number of permutations of n things taken
r at a time. The glyph is the combination of the ( # ) glyph
for number of and the permutation glyph ( !! ) .