對映（對映）和減少（摺疊）向量

向量可以是 map’d 和 fold'd,filter'd andzip`‘d：

Prelude Data.Vector> Data.Vector.map (^2) y
fromList [0,1,4,9,16,25,36,49,64,81,100,121] :: Data.Vector.Vector

減少到單個值：

Prelude Data.Vector> Data.Vector.foldl (+) 0 y
66