Chapter 09 Python Lists and Dictionaries¶

# 01 Introduction to Lists

zoo_animals = ["pangolin", "cassowary", "sloth", "panda"];
# One animal is missing!

if len(zoo_animals) > 3:
    print ("The first animal at the zoo is the " + zoo_animals[0])
    print ("The second animal at the zoo is the " + zoo_animals[1])
    print ("The third animal at the zoo is the " + zoo_animals[2])
    print ("The fourth animal at the zoo is the " + zoo_animals[3])

# 02 Access by Index

numbers = [5, 6, 7, 8]

print ("Adding the numbers at indices 0 and 2...")
print (numbers[0] + numbers[2])
# Your code here!
print ("Adding the numbers at indices 1 and 3...")
print (numbers[1] + numbers[3])

# 04 Late Arrivals and List Length

suitcase = []
suitcase.append("sunglasses")

# Your code here!
suitcase.append("shirt")
suitcase.append("trousers")
suitcase.append("coat")

list_length = len(suitcase)# Set this to the length of suitcase

print ("There are %d items in the suitcase." % (list_length))
print (suitcase)

# 05 List Slicing

suitcase = ["sunglasses", "hat", "passport", "laptop", "suit", "shoes"]

first = suitcase[:2] # same as suitcase[0: 2]   # The first two items
middle = suitcase[2:4]  # Third and fourth items
last = suitcase[len(suitcase) - 2:] # same as suitcase[len(suitcase) - 2: len(suitcase)]   
# The last two items

print (first)
print (middle)
print (last)

# 06 Slicing Lists_and Strings

animals = "catdogfrog"
cat = animals[:3]  # The first three characters of animals
dog = animals[3:6]   # The fourth through sixth characters
frog = animals[6:]  # From the seventh character to the end

print (cat)
print (dog)
print (frog)

# 07 Maintaining Order

animals = ["aardvark", "badger", "duck", "emu", "fennec fox"]
duck_index = animals.index("duck")    # Use index() to find "duck"

print(duck_index)

# Your code here!
animals.insert(duck_index, "cobra")

print (animals) # Observe what prints after the insert operation

# 08 For One and All

my_list = [1,9,3,8,5,7]

for number in my_list:
    # Your code here
    print (number * 2)
    

# 09 More with for

start_list = [5, 3, 1, 2, 4]
square_list = []

# Your code here!
for e in start_list:
    square_list.append(e ** 2)

square_list.sort()
print (square_list)

# 10 This Next Part is Key

# Assigning a dictionary with three key-value pairs to residents:
residents = {'Puffin' : 104, 'Sloth' : 105, 'Burmese Python' : 106}

print (residents['Puffin']) # Prints Puffin's room number

# Your code here!
print (residents["Sloth"])
print (residents["Burmese Python"])

# 11 New Entries

menu = {} # Empty dictionary
menu['Chicken Alfredo'] = 14.50 # Adding new key-value pair
print (menu['Chicken Alfredo'])

# Your code here: Add some dish-price pairs to menu!
menu['Beef'] = 50.00
menu['pork'] = 20.00
menu['porridge'] = 5.00

print ("There are " + str(len(menu)) + " items on the menu.")
print (menu)

# 12 Changing Your Mind

# key - animal_name : value - location
zoo_animals = { 'Unicorn' : 'Cotton Candy House',
'Sloth' : 'Rainforest Exhibit',
'Bengal Tiger' : 'Jungle House',
'Atlantic Puffin' : 'Arctic Exhibit',
'Rockhopper Penguin' : 'Arctic Exhibit'}
# A dictionary (or list) declaration may break across multiple lines

# Removing the 'Unicorn' entry. (Unicorns are incredibly expensive.)
del zoo_animals['Unicorn']

# Your code here!
del zoo_animals['Sloth']
del zoo_animals['Bengal Tiger']
zoo_animals['Rockhopper Penguin'] = 'What?'

print (zoo_animals)

inventory