Lists

🎨 []

🖌 .append(...)

append: to put after, to place at the end

names = []
while True:
    name = input("Give me a name: ")
    if name == 'q':
        break
    names.append(name)
    
print(names)

Give me a name: John
Give me a name: Peter
Give me a name: Michael
Give me a name: James
Give me a name: Sarah
Give me a name: Mary
Give me a name: Quinn
Give me a name: q
['John', 'Peter', 'Michael', 'James', 'Sarah', 'Mary', 'Quinn']

• [] creates an empty list
• .append(...) adds the item to the list
• you can see the contents by printing the list
  • Note the commas
• What happens when you enter no names (enter 'q' the first time)?

names = ['Julia', 'Juan', 'George', 'Gina']
print(names)

['Julia', 'Juan', 'George', 'Gina']

You can define a list with initial contents.

names = ['Julia', 'Juan', 'George', 'Gina']
while True:
    name = input("Give me a name: ")
    if name == 'q':
        break
    names.append(name)
    
print(names)

Give me a name: George
Give me a name: Carson
Give me a name: Carsyn
Give me a name: Jack
Give me a name: q
['Julia', 'Juan', 'George', 'Gina', 'George', 'Carson', 'Carsyn', 'Jack']

You can add to a list that started with contents already.

🎨 len

fruit = ['apple', 'peach', 'pear', 'açaí']
how_many = len(fruit)
print(how_many)

4

You can find the length, or size, of a list using the len function.

🖌 for

students = ['Julia', 'Juan', 'George', 'Gina']
for name in students:
    print(f"Hello {name}. Welcome to CS 110.")

Hello Julia. Welcome to CS 110.
Hello Juan. Welcome to CS 110.
Hello George. Welcome to CS 110.
Hello Gina. Welcome to CS 110.

👨🏻‍🎨 Bullet styles

Write a program that:

1. Asks the user for a series of items
   • The user inputs q when they are done
2. Print the list of items using the following bullets:
   • *
   • -
   • >

bullet_styles.py

👩🏽‍🎨 Big and Small

Write a program that queries the user for a list of numbers (one number at a time).

Then ask the user what number to use as the boundary between "big" and "small" numbers.

Print "You have {how_many} numbers"

Then print the small numbers with the heading "These are small:"

Then print the bit numbers with the heading "These are big:"

Number: 8
Number: 10
Number: 30
Number: 2
Number: 65
Number: 42
Number: 13
Number: 77
Number: q
Boundary: 20
You have 8 numbers
These are small:
8
10
2
13
These are big:
30
65
42
77

Key Ideas

• Lists!
• []
• .append(...)
• len
• for