K makes this explicit with the ‘where’ function which converts a Boolean array into the list of indices of true values. Thus, x[4 5 6] is index access (“at

K makes this explicit with the ‘where’ function which converts a Boolean array into the list of indices of true values. Thus, x[4 5 6] is index access (“at”); also x@4 5 6 x[&x>3] is “x at where x is greater than 3” ; can also be written x@&x>3