Lesson 12

Review Lists, Loops, and Functions

List Initialization

a = [0, 0, 0]
b = 3 * [0]
c = []
c.append(0)
c.append(0)
c.append(0)
print(a)
print(b)
print(c)

Accessing List Elements by Index

a = [2, 0, 3]
print(a[0])
print(a[3])

The len() Function

a = [2, 0, 3]
a.append(10000)
print(len(a))

For Loops with range()

for counter in range(5):
    print(counter)

for counter in range(1, 5):
    print(counter)

for counter in range(1, 5, 2):
    print(counter)

Functions

def foo():
    print("printint inside the foo function")


def say_hello(name: str):
    print("hello", name)

Exercise 1

Exercise 1

Define a function named print_numbers that prints the numbers 0-10.

Extensions:

  1. Write a function print_numbers_up_to(n: int) that prints the numbers 0-n.

  2. Write a function print_numbers_between(a: int, b: int) that prints the numbers a-b.

    1. Write a function print_even_numbers_between(a: int, b: int) that prints the even numbers between a and b

Iterating Over a List

index = 0
names = ['Charles', 'Capri', 'Lucas', 'Tim', 'Yong', 'Justyna']
print(names[index])


for index in range(3):
    print(index)

How can we print out all of the names in the names list?

Exercise 2

Exercise 2

Define a function named print_list(any_list: List[Any]) that takes a list as an argument and prints out all of the lists elements.

Extensions:

  1. Write a function to print the first half of a list.

  2. Write a function to print the second half of a list.

  3. Write a function to print put rounded numbers from a list of floats.

  4. Write a function to print a list in reverse order.

  5. Write a function to print the square of each number in a list.

Conditions in For Loops

Exercise 3

Exercise 3

Define a function named print_element_in_list(any_list: List[Any], element: Any) that takes a list as an argument and prints out the element if it is in the list.

Extensions:

  1. Write a function to print the indices of an element if it is in a list.

  2. Write a function to print the elements between two numbers a and b.

  3. Write a function to print all the even numbers in a list.

  4. Write a function to print all of the prime numbers in a list.

Return Values from Functions

name = input('What is your name')

def give_me_5() -> int
    return 5

hand = give_me_5()
print(hand)

def roll_die() -> int:
    return random.randint(1,6)

random_side = roll_die()

def is_adult(age: int) -> bool:
    return age >= 18

Exercise 4

Exercise 4

Define a function named roll_die(sides: int) -> int that returns a random int between 1 and sides.

Extensions:

  1. Write a function to returns the first element in a list

  2. Write a function to returns the last element in a list

  3. Write a function that returns True if a string starts with the letter ‘t’

  4. Write a function that returns True if a string starts with the letter c where c is an argument.

  5. Write a function that returns a list of length n with random elements between 1 and 100.

  6. Write a function that returns a list of length n with random elements between a and b.

Using return to Stop Execution

Exercise 5

Exercise 5

Define a function named is_in_list(lst: List[int], element: int) -> bool that returns a True if and only if element is found in lst.

Extensions:

  1. Write a function that returns True if an element is not in a list.

  2. Write a function that returns True if two lists have at least one element in common.

Python’s in Keyword