Appendix G — Assignment 2

G.1 (1) What statement creates a function?

1. def
   
2. definition
   
3. Def
   
4. Definition

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G.2 (2) According to the following program:

def math():   
    math = 100
    print(math)   

def nsysu():   
    math = "interesting"
    math()    
    print(math)  

math = "I love math!"  

What should the ouputs look like when you run nsysu() and print(math)?

1. I love math! I love math!, I love math!
   
2. interesting, I love math!
   
3. 100 100, 100
   
4. 100 interesting, I love math!

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G.3 (3) What does from math import * if you have a file named math.py, which stores many functions?

1. import the first function in math.py
   
2. import all functions from math.py
   
3. import the last function in math.py
   
4. meaningless

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G.4 (4) How do you use the function linspace() in numpy according to import numpy as np?

1. linspace()
   
2. np linspace()
   
3. numpy.linspace()
   
4. np.linspace()

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G.5 (5) What is the data type of None?

1. str
   
2. Nonetype
   
3. bool
   
4. list

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G.6 (6) Why are functions adventageous to have in your programs?

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Functions reduce the need for duplicate code. This makes programs shorter, easier to read, and easier to update.

G.7 (7) What happens to variables in a local scope when the function call returns?

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When a function returns, the local scope is destroyed, and all the variables in it are forgotten.

G.8 (8) How can you force a variable in a function to refer to the global variable?

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A global statement will force a variable in a function to refer to the global variable.

G.9 (9) Write a function named collatz() that has one parameter named number. If number is even, then collatz should print number // 2 and return this value. If number is odd, then collatz should print and return 3 * number + 1.

def collatz(number):
    """
    Parameters
    ----------
    number: int
        The input number.
    Returns
    -------
    number: int
        The ouput number.
    """
    # coding your answer here
    if number % 2 == 0:
        number = number // 2
    else:
        number = 3 * number + 1
    print(number)
    return(number)

G.10 (10) Continuing from the previous question, write a program that allows the user to type in an interger and that keeps callig collatz() on the number until the function returns the value 1.

sample output

Enter number:   
3      
10   
5   
16   
8   
4   
2   
1

# coding your answer here
number = int(input("Enter number: \n"))
while number != 1:
    number = collatz(number)