Day 2 Review

Yesterday we looked at lists and for loops.

Lists

# define a list 
my_list = ["unicorn", "fairy", "hippogriff", "centaur", "dragon"]
print(my_list)

['unicorn', 'fairy', 'hippogriff', 'centaur', 'dragon']

# access an element 
my_element = my_list[2]
print(my_element)

hippogriff

# access a slice 
my_slice = my_list[1:4]
print(my_slice)

['fairy', 'hippogriff', 'centaur']

# a slice with steps. This accesses every other element in the list
step_slice = my_list[::2]
print(step_slice)

['unicorn', 'hippogriff', 'dragon']

# change an element
my_list[1] = "goblin"
print(my_list)

['unicorn', 'goblin', 'hippogriff', 'centaur', 'dragon']

# add an element 
my_list.append("elf")
print(my_list)

['unicorn', 'goblin', 'hippogriff', 'centaur', 'dragon', 'elf']

For loops

# iterate over numbers 
for i in range(10):
    print(i)

0
1
2
3
4
5
6
7
8
9

# iterate over lists 
for creature in my_list:
    print("Ahhh! It's a {}!".format(creature))

Ahhh! It's a unicorn!
Ahhh! It's a goblin!
Ahhh! It's a hippogriff!
Ahhh! It's a centaur!
Ahhh! It's a dragon!
Ahhh! It's a elf!

# iterate over multiple lists at the same time
colors = ["green", "blue", "silver", "gold", "purple", "yellow"]
for color, creature in zip(colors, my_list):
    print("Look! It's a {} {}!".format(color, creature))

Look! It's a green unicorn!
Look! It's a blue goblin!
Look! It's a silver hippogriff!
Look! It's a gold centaur!
Look! It's a purple dragon!
Look! It's a yellow elf!

# iterate over elements while keeping track of their indicies
for i, creature in enumerate(my_list):
    print("{} is element number {}".format(creature, i))

unicorn is element number 0
goblin is element number 1
hippogriff is element number 2
centaur is element number 3
dragon is element number 4
elf is element number 5

Back to day 3