Due by 11:59pm on Tuesday, July 1.

Starter Files

Download lab01.zip.

Required Questions

Review

Important: If the python3 command doesn't work, please try using python or py.

python3 ok -q FUNCTION

print("DEBUG:", x)

>>> 1 / 5
0.2

>>> 25 / 4
6.25

>>> 4 / 2
2.0

>>> 5 / 0
ZeroDivisionError

>>> 1 // 5 # truncate result of true division
0

>>> 25 // 4
6

>>> 4 // 2
2

>>> 5 // 0
ZeroDivisionError

>>> 1 % 5
1

>>> 25 % 4
1

>>> 4 % 2
0

>>> 5 % 0
ZeroDivisionError

x % y == 0

def what_prints():
    print('Hello World!')
    return 'Exiting this function.'
    print('This course is awesome!')

>>> what_prints()
Hello World!
'Exiting this function.'

What Would Python Display? (WWPD)

Q1: Return and Print

Use Ok to test your knowledge with the following "What Would Python Display?" questions:

python3 ok -q return-and-print -u
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>>> def welcome():
...     print('Go')
...     return 'hello'
...
>>> def cal():
...     print('Bears')
...     return 'world'
...
>>> welcome()
______
Go
'hello'
>>> print(welcome(), cal())
______
Go
Bears
hello world

Q2: WWPD: What If?

Use Ok to test your knowledge with the following "What Would Python Display?" questions:

python3 ok -q if-statements -u
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Hint: print (unlike return) does not cause the function to exit.

>>> def ab(c, d):
...     if c > 5:
...         print(c)
...     elif c > 7:
...         print(d)
...     print('foo')
>>> ab(10, 20)
______
10
foo

>>> def bake(cake, make):
...     if cake == 0:
...         cake = cake + 1
...         print(cake)
...     if cake == 1:
...         print(make)
...     else:
...         return cake
...     return make
>>> bake(0, 29)
______
1
29
29
>>> bake(1, "mashed potatoes")
______
mashed potatoes
'mashed potatoes'

Debugging Quiz

Q3: Debugging Quiz

The following is a quick quiz on different debugging techniques that will be helpful for you to use in this class. You can refer to the debugging article to answer the questions.

Use Ok to test your understanding:

python3 ok -q debugging-quiz -u
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Write Code

Q4: Falling Factorial

Let's write a function falling, which is a "falling" factorial that takes two arguments, n and k, and returns the product of k consecutive numbers, starting from n and working downwards. When k is 0, the function should return 1.

def falling(n, k):
    """Compute the falling factorial of n to depth k.

    >>> falling(6, 3)  # 6 * 5 * 4
    120
    >>> falling(4, 3)  # 4 * 3 * 2
    24
    >>> falling(4, 1)  # 4
    4
    >>> falling(4, 0)
    1
    """
    "*** YOUR CODE HERE ***"

Use Ok to test your code:

python3 ok -q falling
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Q5: Divisible By k

Write a function divisible_by_k that takes positive integers n and k. It prints all positive integers less than or equal to n that are divisible by k from smallest to largest. Then, it returns how many numbers were printed.

def divisible_by_k(n, k):
    """
    >>> a = divisible_by_k(10, 2)  # 2, 4, 6, 8, and 10 are divisible by 2
    2
    4
    6
    8
    10
    >>> a
    5
    >>> b = divisible_by_k(3, 1)  # 1, 2, and 3 are divisible by 1
    1
    2
    3
    >>> b
    3
    >>> c = divisible_by_k(6, 7)  # There are no integers up to 6 that are divisible by 7
    >>> c
    0
    """
    "*** YOUR CODE HERE ***"

Use Ok to test your code:

python3 ok -q divisible_by_k
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Q6: Double Eights

Write a function that takes in a number and determines if the digits contain two adjacent 8s.

def double_eights(n):
    """Return true if n has two eights in a row.
    >>> double_eights(8)
    False
    >>> double_eights(88)
    True
    >>> double_eights(2882)
    True
    >>> double_eights(880088)
    True
    >>> double_eights(12345)
    False
    >>> double_eights(80808080)
    False
    """
    "*** YOUR CODE HERE ***"

Use Ok to test your code:

python3 ok -q double_eights
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Check Your Score Locally

You can locally check your score on each question of this assignment by running

python3 ok --score

This does NOT submit the assignment! When you are satisfied with your score, submit the assignment to Gradescope to receive credit for it.

Submit Assignment

Submit this assignment by uploading any files you've edited to the appropriate Gradescope assignment. Lab 00 has detailed instructions. Correctly completing all questions is worth one point for regular section students and two points for mega section students.

If you are in regular section, be sure to fill out your TA's attendance form before you leave section. Attending lab section is worth one point for regular section students.

Optional Questions

These questions are optional. If you don't complete them, you will still receive credit for this assignment. They are great practice, so do them anyway!

Q7: Two of Three

Write a function that takes three positive numbers as arguments and returns the sum of the squares of the two smallest numbers. Use only a single line for the body of the function.

def two_of_three(i, j, k):
    """Return m*m + n*n, where m and n are the two smallest members of the
    positive numbers i, j, and k.

    >>> two_of_three(1, 2, 3)
    5
    >>> two_of_three(5, 3, 1)
    10
    >>> two_of_three(10, 2, 8)
    68
    >>> two_of_three(5, 5, 5)
    50
    """
    return _____

Hint: Consider using the max or min function:

>>> max(1, 2, 3)
3
>>> min(-1, -2, -3)
-3

Use Ok to test your code:

python3 ok -q two_of_three
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Use Ok to run the local syntax checker (which checks that you used only a single line for the body of the function):

python3 ok -q two_of_three_syntax_check

Q8: Middle Number

Implement middle by writing a single return expression that evaluates to the value that is neither the largest or smallest among three different integers a, b, and c.

Hint: Try combining all the numbers and then taking away the ones you don't want to return by using the built-in min and max functions.

>>> max(1, 2, 3)
3
>>> min(-1, -2, -3)
-3

def middle(a, b, c):
    """Return the number among a, b, and c that is not the smallest or largest.
    Assume a, b, and c are all different numbers.

    >>> middle(3, 5, 4)
    4
    >>> middle(30, 5, 4)
    5
    >>> middle(3, 5, 40)
    5
    >>> middle(3, 5, 40)
    5
    >>> middle(30, 5, 40)
    30
    """
    return ____

Use Ok to test your code:

python3 ok -q middle
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Q9: Largest Factor

Write a function that takes an integer n that is greater than 1 and returns the largest integer that is smaller than n and evenly divides n.

def largest_factor(n):
    """Return the largest factor of n that is smaller than n.

    >>> largest_factor(15) # factors are 1, 3, 5
    5
    >>> largest_factor(80) # factors are 1, 2, 4, 5, 8, 10, 16, 20, 40
    40
    >>> largest_factor(13) # factors are 1, 13
    1
    """
    "*** YOUR CODE HERE ***"

Hint: To check if b evenly divides a, use the expression a % b == 0, which can be read as, "the remainder when dividing a by b is 0."

Use Ok to test your code:

python3 ok -q largest_factor
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Q10: Multiple

Write a function that takes in two numbers and returns the smallest number that is a multiple of both.

def multiple(a, b):
    """Return the smallest number n that is a multiple of both a and b.

    >>> multiple(3, 4)
    12
    >>> multiple(14, 21)
    42
    """
    "*** YOUR CODE HERE ***"

Use Ok to test your code:

python3 ok -q multiple
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