2 select - form a list by selecting element-values from a given list
14 If y is to be the name of a user-defined function, select(x, y)
15 returns a list whose members are the values z of elements of x
16 for which the function at z tests as nonzero.
17 The list x is not changed. The order of the returned list is
23 > A = list(2,4,6,8,2,7)
24 > print select(A, "f")
26 list (3 elements, 3 nonzero):