Today’s Ruby Tuesday cover’s Array#*.

`Array#*`

either takes a integer, N, as its argument, in which case it concatenates N copies of the array together and uses the result as it return value.

[1, 2, 3, 4, 5] * 3 % => [1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5] ["a", "b", "c"] * 4 % => ["a", "b", "c", "a", "b", "c", "a", "b", "c", "a", "b", "c"] [1, [:a, [:b, [:c]]]] * 2 % => [1, [:a, [:b, [:c]]], 1, [:a, [:b, [:c]]]]

Or it can take a string as its argument, in which case, it returns a flattened join of the items in the array with the string argument as the separator.

["a", "b", "c"] * "," % => "a,b,c" ["a", "b", "c"] * "at" % => "aatbatc" [1, 2, 3, 4, 5] * '' % => "12345" [:x, :y, :z] * ';' % => "x;y;z" [[:a, 1], [:b, 2], [:c, 3]] * ';' % => "a;1;b;2;c;3" [1, [:a, [:b, [:c]]]] * ';' % => "1;a;b;c"

Notice how multiplying by a string returns a flattened array joined together, instead of just the top level elements of an array with `to_s`

called on them joined together.

–Proctor