Lab 3.04 - Aliasing & Scope

Aliasing

• Will updating b affect a? Explain why or why not?

    a = [1, 2, 4]
    b = a
  

  
  

• Predict what my_list list will print out when this code is run. If you are not sure check the code by copying and running it.

    # input: a list of ints
    # output: an int
    def update_list(a_list):
        a_list[3] = "yo"
        b = a_list[4]
        b = 100
  
    my_list = [1, 2, 3, 4, 5]
    update_list(my_list)
  

  
  

Scope

• Draw a stack diagram for the following:

    var_1 = "kittens"
    var_2 = "cookies"
  
    # input: a string
    # output: a string
    def my_function(my_favorite_things):
        song_lyrics = "rain drops on roses,"
        combined_song = song_lyrics + my_favorite_things
        return combined_song
  
    # input: a string
    # output: a string
    def my_function_2(item, item2):
        full_lyrics = item + "on " + item2
        full_song = my_function(full_lyrics)
        return full_song
  
    my_song = my_function_2(var_1, var_2)
  

  
  
  
  

• Write down what (if anything) is wrong with the following code. If there was an issue write out how to fix it. If you are unsure copy and run the code and fix it.

1.

var_1 = 'cat'
var_2 = 'dog'

def print_out_my_favorite(favorite_pet):
    if favorite_pet == var_1:
        print("My favorite pet is the cat.")
    if favorite_pet == var_2:
        print("My favorite pet is the dog.")
    var_2 = "cat"

print_out_my_favorite(var_1)
print(var_2)

2.

var_1 = 'cat'
var_2 = 'dog'

def print_out_my_favorite(favorite_pet):
    var_1 = 'dog'
    var_2 = 'cat'
    if favorite_pet == var_1:
        print("My favorite pet is the cat.")
    if favorite_pet == var_2:
        print("My favorite pet is the dog.")

print_out_my_favorite(var_1)
print(var_1 + " " + var_2)

3.

var_1 = 'cat'
var_2 = 'dog'

def print_out_my_favorite(favorite_pet):
    if favorite_pet == var_1:
        print("My favorite pet is the cat.")
    if favorite_pet == var_2:
        print("My favorite pet is the dog.")

print_out_my_favorite(var_1)
print(var_2)

• Write a program that has a global variable, my_num. Create three functions that update my_num:
  1. add2: this function adds 2 to my_num
  2. multiply_num: this function takes in a parameter, multiplier, and multiplies my_num by that parameter
  3. add2_and_multiply: this function takes in a parameter, multiplier, and calls add2, then calls multiply_num.