Python Practice

Repository for me to store my practice programs and coursework as I teach myself Python and work through Python Crash Course.

Chapter 2

2.1 Simple Message

The first "Hello World type program"

message = "This is a simple message. Hurray!"
print(message)

This first program will print the message. message = will set whatever string literal to the variable "message" which is then called by print(message) resulting in the following output:

This is a simple message. Hurray!

2.1 Simple Messages

This code shows a simple cocatenation of two separate messages I've made. this time we have a message and a message2 you can combine the outputs of these two separate variables by doing print(message + message2)

#Simple hello message
message = "Oh Hello there!  "
print (message)
message2 = "This is concatenation"
print(message + message2)

The code above results in the following output:

Oh Hello there! This is concatenation

2.3 Personal Message

The following code does a few things we've already covered and a few new thins.

message_name = "matthew compton"

message = "Hello " + message_name.title() + ". How are you doing today?\nWould you like to learn some Python?"
print(message)

second_name = "Jeremy Simpson"

# 2_4 Practice Famous Quote
print(second_name.upper())
print(second_name.lower())
print(second_name.title())

# 2_5 Practice
quote = 'Winson Churchill once said, "A joke is a very serious thing."\n'
print(quote)

# 2_6 Practice Famous Quote 2
famous_person = "winston churchill "
famous_quote = famous_person.title() + 'once said, "A joke is a very serious thing."\n'
print(famous_quote)

You may have noticed message_name.title() this will make each word included in the variable uppercase. Displaying as follows:

Matthew Compton

all \n does is create a new line. Given name = 'matthew compton' there are several things we could do wit this data. print(name.upper()) will give us

MATTHEW COMPTON

When we are given print(name.lower()) we will get:

matthew compton

This won't change simply because it was already lowercase but say we gave name = 'MaTtHeW CoMpToN' and then tried print(name.lower()) we would receive:

matthew compton

2.8 Numbers

Code:

# The following file is meant to show how to work with various math functions in Python, as well as properly including numerical results in a string
print("5 + 3 = " + str(5+3))
print("4 * 2 = "+ str(4*2))
print("16 / 2 = "+str(16/2))
print("2^3 = "+ str(2**3))

favorite_number = 33
message= "My favorite number is: "+ str(favorite_number) + " pretty neat huh?"
print(message)

The above code shows how math functions work in python. The + and - signs work as you would expect however be careful as in most programming languages, Python included. When you see == , this actually means 'is equal to' when evaluating certain functions. You may have noticed another new thing showing up, print("5 + 3 = " + str(5+3)) str tells python to print whatever is enveloped to print as a string rather than whatever other value. Everything above outputs:

5 + 3 = 8
4 * 2 = 8
16 / 2 = 8.0
2^3 = 8
My favorite number is: 33 pretty neat huh?

Chapter 3

3.1 Working with Indexes

Code:

friends = ['cody','josh','chase','preston']
print(friends[0].title())
print(friends[1].title())
print(friends[2].title())
print(friends[3].title())

The above code has our first example of an index in Python, you can declare an index by adding brackets []. For example: my_index = [] this will create an empty list. For the code above print(friends[0].title()) will output:

Cody

Aside from .title() which we know how works print(friends[0]) will output whatever data is stored in the first location in the index. Which in Python starts at [0].

3.2 Greetings

Code:

friends = ['cody','josh','chase','preston']
print("Why hello there " + friends[0].title() + " how are you doing?")
print("Why hello there " + friends[1].title() + " how are you doing?")
print("Why hello there " + friends[2].title() + " how are you doing?")
print("Why hello there " + friends[3].title() + " how are you doing?")

This code is a slight modification of 3.1. The biggest difference is rather than print(friends[0].title()) we have: print("Why hello there " +friends[0].title() + " how are you doing?"). This just adds a simple greeting message to the above output resulting in:

Why hello there Cody how are you doing?

I could add whatever message I wanted to this like perhapts I'd want to do. print(friends[0].title() + ' have you heard of Python before?' which would simply output:

Cody have you heard of Python before?

3.3 My Own List

Code:

motorcycles = ['BMW','Honda','Harley Davidson','Ducati']
print(motorcycles)
message = "My favorite motorcycle is a "+motorcycles[0]
print(message)

print("I would like to own a "+motorcycles[1]+ " motorcycle.\n")

motorcycles.append('Yamaha')
print(motorcycles )

motorcycles = []

motorcycles.append('honda')
motorcycles.append('yamaha')
motorcycles.append('suzuki')

print(motorcycles)

motorcycles.insert(0,'ducati')
print(motorcycles)

del motorcycles[0]
print(motorcycles)

del motorcycles[2]
print(motorcycles)

motorcycles = ['yamaha','honda','harley davidson','ducati']
last_motorcycle = motorcycles.pop()

print(motorcycles)
print("The last motorcycle I owned was a "+last_motorcycle.title())

first_owned = motorcycles.pop(0)
print('The first motorcycle I owned was a '+ first_owned.title())

motorcycles = ['yamaha','honda','harley davidson','ducati']

waytooexpensive = 'ducati'
motorcycles.remove(waytooexpensive)
print(motorcycles)
print("\nA "+waytooexpensive.title() + " is too expensive for my tastes.")

Here I've done some stuff we already know and added a few things we don't yet. First I define my own list with motorcycles = ['BMW','Honda','Harley Davidson','Ducati'] now say I wanted to add something to this list that I didn't have earlier. What I would do in this case is motorcycles.append('kawasaki') now when I try print(motorcycles) we would see:

['BMW', 'Honda', 'Harley Davidson', 'Ducati', 'kawasaki']

append adds to the end of the list but what if I wanted to add an item at a particular spot. First let's delete the last item in that list with del motorcycles [4] which deletes the item at place 4 in the list (remember that lists begin at spot [0] in Python and most languages for that matter) let's now add Kawasaki to the center of the list. We can do this with motorcycles.insert(2,'Kawasaki') and when we print this we will see:

['BMW', 'Honda', 'Kawasaki', 'Harley Davidson', 'Ducati']

3.4 Guest List

Code:

famous_guest_list = ['napoleon bonaparte','george orwell','alexander the great']

message= "Hello "+famous_guest_list[0].title() + " I'd like to have you as a guest at my dinner party!\n"
print(message)
message= "Hello "+famous_guest_list[1].title() + " I'd like to have you as a guest at my dinner party!\n"
print(message)
message= "Hello "+famous_guest_list[2].title() + " I'd like to have you as a guest at my dinner party!\n"
print(message)

Here we create a list of famous people to be at my dinner party. We then print a message to invite them.

3.5 Changing Guest List

Code:

famous_guest_list = ['napoleon bonaparte','george orwell','alexander the great']

print("Oh no! it turns out "+famous_guest_list[0].title() + " won't be able to make it!\n")
famous_guest_list[0] = 'ronald reagan'

message= "Hello "+famous_guest_list[0].title() + " I'd like to have you as a guest at my dinner party!\n"
print(message)
message= "Hello "+famous_guest_list[1].title() + " I'd like to have you as a guest at my dinner party!\n"
print(message)
message= "Hello "+famous_guest_list[2].title() + " I'd like to have you as a guest at my dinner party!\n"
print(message)

This code takes what we did in 3.4 with one exception. Napoleon wasn't able to make it, instead we changed the person who was going to attend out with Ronald reagan.

3.6 More Guests

Code:

famous_guest_list = ['napoleon bonaparte','george orwell','alexander the great']

print("Oh no! it turns out "+famous_guest_list[0].title() + " won't be able to make it!\n")
famous_guest_list[0] = 'ronald reagan'

message= "Hello "+famous_guest_list[0].title() + " I'd like to have you as a guest at my dinner party!\n"
print(message)
message= "Hello "+famous_guest_list[1].title() + " I'd like to have you as a guest at my dinner party!\n"
print(message)
message= "Hello "+famous_guest_list[2].title() + " I'd like to have you as a guest at my dinner party!\n"
print(message)

print('Hey everyone, luckily I was able to find a larger table to accommodate more people!\n')
famous_guest_list.insert(0,'franklin delano roosevelt')
famous_guest_list.insert(2,'john f kennedy')
famous_guest_list.append('thomas jefferson')

message= "Hello "+famous_guest_list[0].title() + " I'd like to have you as a guest at my dinner party!\n"
print(message)
message= "Hello "+famous_guest_list[1].title() + " I'd like to have you as a guest at my dinner party!\n"
print(message)
message= "Hello "+famous_guest_list[2].title() + " I'd like to have you as a guest at my dinner party!\n"
print(message)
message= "Hello "+famous_guest_list[3].title() + " I'd like to have you as a guest at my dinner party!\n"
print(message)
message= "Hello "+famous_guest_list[4].title() + " I'd like to have you as a guest at my dinner party!\n"
print(message)
message= "Hello "+famous_guest_list[5].title() + " I'd like to have you as a guest at my dinner party!\n"
print(message)

Here we have the same code as 3.4 except we have added more guests inserting them at different places in the guest list. If we printed the guest list it would look like this:

['franklin delano roosevelt', 'ronald reagan', 'john f kennedy', 'george orwell', 'alexander the great', 'thomas jefferson']

3.7 Shrinking Guest List

Code:

famous_guest_list = ['napoleon bonaparte','george orwell','alexander the great']
print("Oh no! it turns out "+famous_guest_list[0].title() + " won't be able to make it!\n")
famous_guest_list[0] = 'ronald reagan'
print('Hey everyone, luckily I was able to find a larger table to accomodate more people!\n')
famous_guest_list.insert(0,'franklin delano roosevelt')
famous_guest_list.insert(2,'john f kennedy')
famous_guest_list.append('thomas jefferson')
print("Unfortunately that table won't be able to arrive in time. Instead I only have space for two guests")



persontoleave = famous_guest_list.pop()
print('Sorry '+persontoleave.title()+" there just wasn't enough room for you. \n")
persontoleave = famous_guest_list.pop()
print('Sorry '+persontoleave.title()+" there just wasn't enough room for you. \n")
persontoleave = famous_guest_list.pop()
persontoleave = famous_guest_list.pop()
print('Sorry '+persontoleave.title()+" there just wasn't enough room for you. \n")

print("I'm happy to say that you "+famous_guest_list[0].title()+" are still invited!\n")
print("I'm happy to say that you "+famous_guest_list[1].title()+" are still invited!\n")

del famous_guest_list[0]
del famous_guest_list[0]
print(famous_guest_list)

The above code if you've kept up with it will result in an empty guest list. the persontoleave = famous_guest_list.pop() line gets rid of the last item in the list, imagine the list as a stack and you are popping off the top.

3.8 Seeing The World

Code:

places_i_want_to_visit = ['taj mahal','the equator','moscow','australia','los angeles'] #declares the list initially
print(places_i_want_to_visit) #prints the data as is

Will output:

['taj mahal', 'the equator', 'moscow', 'australia', 'los angeles']

print(sorted(places_i_want_to_visit)) #temporarily sorts the data in the list alphabetically, leaving original data

Will output:

['australia', 'los angeles', 'moscow', 'taj mahal', 'the equator']

However the sorted method only temporarily sorts alphabetically

print(places_i_want_to_visit) #shows that the original list still exists

['taj mahal', 'the equator', 'moscow', 'australia', 'los angeles']

places_i_want_to_visit.reverse() #reverses the order of the list
print(places_i_want_to_visit) #prints reversed list

This will as expected reverse the list. Here's the output:

['los angeles', 'australia', 'moscow', 'the equator', 'taj mahal']

places_i_want_to_visit.reverse() #reverses again reverting it back to original list
print(places_i_want_to_visit) #prints newly returned original list

To revert back is easy. All that needs to be done is reverse again to get the original list.

['taj mahal', 'the equator', 'moscow', 'australia', 'los angeles']

places_i_want_to_visit.sort() #permanently sorts list alphabetically
print(places_i_want_to_visit) #prints new list

To permanently sort your list alphabetically you can use the sort() function. The above code results in this:

['australia', 'los angeles', 'moscow', 'taj mahal', 'the equator']

Be careful though you will NOT be able to get the original order of this list after doing this!

places_i_want_to_visit.sort(reverse=True) #permanently reverses list alphabetically
print(places_i_want_to_visit) #prints new list

Finally if we want to sort in reverse alphabetical all we have to add in the function is sort(reverse=True) Resulting in:

['the equator', 'taj mahal', 'moscow', 'los angeles', 'australia']

The above code introduces various methods we can use to sort data in a list. First we can temporarily sort data alphabetically using the sorted method in the example print(sorted(places_i_want_to_visit)) I can temporarily sort the list alphabetically without changing the original list order. If we want to reverse the list, say in a situation where you want to show a list of newest to oldest items you could use places_i_want_to_visit.reverse() and it will reverse your list for you.

3.9 Dinner Guests

Code:

famous_guest_list = ['napoleon bonaparte','george orwell','alexander the great']
print('There ia a total of '+str(len(famous_guest_list))+ ' guests coming to my dinner party.')

This code is rather simple. We are declaring our famous guest list with the original three members. The real game changer is print('There is a total of ' + str(len(famous_guest_list)) + ' guests coming to my dinner party.') This will output:

There are a total of 3 guests coming to my dinner party.

We can use len() to find the length of a particular list. This does start with one however so we wouldn't have to account for anything starting at 0.

3.9 Every Function

Code:

languages = ['english','german','french','spanish'] #Creates original list of languages

languages.append('russian') #appends or  adds to end of list
print(languages)

languages.insert(2,'swahili') #inserting at place 2 in list swahili
print(languages)

languages.remove('english') #removes data = english
print(languages)

print(languages.pop())#removes and returns last item in list
print(languages)

del languages[2] #deletes language at second spot
print(languages)

languages.append('english') #adds back english
languages.append('mandarin') #adds mandarin
print(languages)

print(sorted(languages)) #temporarily sorts alphabetically

languages.reverse() #reverses order of languages
print(sorted(languages)) #temporarily alphabetically sorts again

languages.reverse() #reverses back to original
print(languages)

languages.sort() #perm sorts alphabetically
print(languages)

languages.sort(reverse=True) #reverses alphabetical sort
print(languages)



print('The list is now ' + str(len(languages)) +' languages long.')

This file contains everything we've learned in Chapter 3 Line by line this code outputs this:

['english', 'german', 'french', 'spanish', 'russian']

['english', 'german', 'swahili', 'french', 'spanish', 'russian']

['german', 'swahili', 'french', 'spanish', 'russian']

russian

['german', 'swahili', 'french', 'spanish']

['german', 'swahili', 'spanish']

['german', 'swahili', 'spanish', 'english', 'mandarin']

['english', 'german', 'mandarin', 'spanish', 'swahili']

['english', 'german', 'mandarin', 'spanish', 'swahili']

['german', 'swahili', 'spanish', 'english', 'mandarin']

['english', 'german', 'mandarin', 'spanish', 'swahili']

['swahili', 'spanish', 'mandarin', 'german', 'english']

The list is now 5 languages long.

Chapter 4

4.1 Pizzas

Code:

pizzas = ['pepperoni','cheese','sausage']
for pizza in pizzas:
    print('I like ' + pizza.title() + ' pizza!\n')

print('Pizza is just very good, I like to eat it all the time.\n')

Here we see our first for each loop. This is going to be very useful in the future. What the above code is doing is for pizza in list pizzas it'll loop through until there are none left. The syntax could have been different and still output the exact same for example:

pizzas = ['pepperoni','cheese','sausage']
for i in pizzas: 
    print('I like ' + i.title() + ' pizza!\n')
    
print('Pizza is just very good, I like to eat it all the time.\n)

Would output the exact same which is

I like Pepperoni pizza!

I like Cheese pizza!

I like Sausage pizza!

Pizza is just very good, I like to eat it all the time.

4.2 Animals

Code:

animals = ['dog','cat','hamster']

for animal in animals:
    print('I sure would like to have a '+animal.title() +  ' as a pet.\n')
print('All of these animals would make a great pet. ')

This is the same as 4.1 just with animals rather than pizza. Mind you that the last print line will only print once the loop is done because it is outside of the loop.

4.3 Counting to Twenty

Code:

Say we want to do a little more with for loops than just print out the contents of each location in a list. We can actually put some logic in a for loop.

numbers = []
for value in range(1,21):
    numbers.append(value)
print(numbers)

The above code initalizes an empty list called numbers. Then we move on to a for loop starting at position 1 and ending at position 20 (remember Python would normally start at 0) for each value in this range it appends to the list that value. Then when the loop is done it prints the whole list. Final output:

[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]

4.4 One Million

Code:

numbers = []
for value in range(1,1000001):
    numbers.append(value)
print(numbers)

This code is the same as 4.3 however it goes all the way to one million then prints the output. Which runs surprisingly fast in Python.

4.5 Summing a Million

Code:

numbers = []
for value in range(1,1000001):
    numbers.append(value)
print(min(numbers))
print(max(numbers))
print(sum(numbers))

The above code shows some functions you can use with a list. We take what we did in 4.4 and find the min,max, and sum of one million. Here is the output:

1

1000000

500000500000

4.6 Odd Numbers

Code:

numbers = []
for value in range (1,21,2):
    numbers.append(value)
    print(value)
print(numbers)

This code does the usual of initializing numbers but our for loop has a tiny difference. It is now going by twos. The final numbers list when you run this will look like this:

[1, 3, 5, 7, 9, 11, 13, 15, 17, 19]

4.7 Threes

Code:

#Make a list of the multiples of 3 from 3 to 30. Use a for loop to print the numbers in your list.
numbers = [value *3 for value in range (3,31)]
for number in numbers:
    print(number)

Here, as my verbose commenting states, we make a list of the multiples of 3 from 3 to 30. We then make a for loop to print the numbers in the list. Using list comprehension, you describe the process using which the list should be created.

4.8 Cubes

Code

#Make a list of the first 10 cubes and use a for loop to print out the value of each cube
numbers = []
for number in range(1,11):
    numbers.append(number **3)
    print(number**3)
print(numbers)

This code cubes the each number in range 1-10 and adds this number to the the list. Resulting in this:

1
8
27
64
125
216
343
512
729
1000
[1, 8, 27, 64, 125, 216, 343, 512, 729, 1000]

4.9 Cube Comprehension

Code

numbers = [value **3 for value in range(1,11)]
for number in numbers:
    print(number)

This code does the same and results in the same thing as the code mentioned in 4.8 with the exception that it doesn't print the final list.

4.10 Slices

Code

pizzas = ['pepperoni','cheese','sausage','pineapple','bacon','meat lovers','vegetarian','marinara','white','hawaiian']
print('The first three items in the list are: ' )
for pizza in pizzas[:3]:
    print(pizza.title())

print('Three items from the middle of the list are: ')
for pizza in pizzas[3:6]:
    print(pizza.title())

print('The last three items from the list are: ')
for pizza in pizzas[7:11]:
    print(pizza.title())

This code first inititalizes a list named pizzas and gives it 10 values in the list. When creating a for loop you can actually use for pizza in pizzas[:3]: this by default will work through the first three values in the list. It will output:

Pepperoni
Cheese
Sausage

Next we have for pizza in pizzas[3:6]: this will output:

Pineapple
Bacon
Meat Lovers

Now you may say that hey I though the third position was Sausage? Remember that Python lists start at 0! Anywho next we have for pizza in pizzas[7:11}: this will output:

Marinara
White
Hawaiian

4.11 my pizzas your pizzas

Code

my_pizzas = ['pepperoni','cheese','sausage']
friend_pizzas = ['pepperoni','cheese','sausage']

my_pizzas.append('hawaiian')
friend_pizzas.append('bacon')

print('My favorite pizzas are: ')
for pizza in my_pizzas:
    print(pizza.title())

print("My friend's favorite pizzas are: ")
for pizza in friend_pizzas:
    print(pizza.title())

This results in:

My favorite pizzas are:
Pepperoni
Cheese
Sausage
Hawaiian
My friend's favorite pizzas are:
Pepperoni
Cheese
Sausage
Bacon

4.12 More Loops

Code:

my_foods = ['pizza','falafel','carrot cake','oranges']
friend_foods = ['pizza','falafel','carrot cake','apples']

print("My favorite foods are: ")
for food in my_foods:
    print(food.title())

print("My friend's favorite foods are: ")
for food in friend_foods:
    print(food.title())

This code has nothing new but will result in:

My favorite foods are:
Pizza
Falafel
Carrot Cake
Oranges
My friend's favorite foods are:
Pizza
Falafel
Carrot Cake
Apples