# ShowArrays.py
""" Contains functions that can be used to get practice
with arrays."""

from random import randint as randi

def randiList(L,R,n):
    """ Returns a length-n list of random integers
    selected from the interval [L,R].
    
    PreC: L, R, and n are ints with n>0 and L<R.
    """
    t = []
    for k in range(n):
        r = randi(L,R)
        t.append(r)
    return t

def Add(x,y):
    """ Returns a list of numbers whose elements
    are obtained by adding corresponding elements from
    the lists x and y.
    
    PreC: x and y are lists of numbers with len(x)==len(y)
    """
    z = []
    for k in range(len(x)):
        s = x[k]+y[k]
        z.append(s)
    return z
     
def ScaleAndAdd1(x,a,y):
    """ PreC: x and y are lists of numbers and a is a float."""
    for k in range(len(x)):
       x[k] = a*x[k]+y[k]
       
def ScaleAndAdd2(x,a,y):
    """PreC: x and y are lists of numbers and a is a float"""
    for k in range(len(x)):
       x[k] = a*x[k]+y[k]
    return x

       
def ScaleAndAdd3(x,a,y):
    """PreC: x and y are lists of numbers and a is a float."""
    z = []
    for k in range(len(x)):
       val = a*x[k]+y[k]
       z = z.append(val)
    return z