Quick and easy Python tutorial

tutorial.py

### 1. BASIC STATEMENTS ###

# These are examples of basic data types in Python. They're basically the same 
# in all programming languages but are all presented slightly differently.

# String: "Hello"
# Number: 5
# Boolean: False
# List: []
# Tuple: []

# Prints the computed value of x to the screen. Usually used for debugging.
print('Hello, world!')

# Prints 200
print(10*20)

# Prints True
print(True)

### 2. VARIABLES ###

# Stores the value seperately so it can be reused. This does the same as above.
hello = 'Hello, world!'
print(hello)

# Change the variable. Prints "nope".
hello = 'nope'
print(hello)

### 3. BOOLEAN ALGEBRA ###

# 1 is considered 'truthy'. Any value or object evaluates to true unless it's a 
# 0, False, None or an empty array.
if 1:
    print('1 is true')

# This statement doesn't evaluate to true because these are all falsy values.
if 0 or False or None:
    # Pass just means 'ignore this' when you don't want anything to happen.
    print('Something above is true')

# An empty array is False. 
if []:
    pass

# However an array with values in it is true.
if [0, 1]:
    print('This list is true')
    
### 4. I/O ###

### 5. Data Structures ###

# Create a list of animals and print it.
animals = ['dog', 'cat', 'rabbit']
print(animals)

# Print the first animal in the list. Arrays start from 0 and not 1.
print(animals[0])

# Change the 2nd value (cat to frog).
animals[1] = 'frog'

# Add giraffe onto the end of the list.
animals.append('giraffe')

# There are more data structures such as: 

# 1. Tuples. 
# The same as lists but the size _has_ to stay the same.

# 2. Maps. 
# These are key-value, so a key matches to a value. e.g
# customer01: "Cameroon Broon"
# customer02: "..."

### 6. Iteration ###

# A small set of instructions can be run over and over.
for x in range(0, 10):
    # This will print 11 times (not 10, because 0 is the start, not 1).
    # The str(x) function makes x into a string. Only strings can be added onto
    # strings. Likewise int(x) makes a string (with a number inside) into a 
    # proper python number.
    print("Times this function has been run: " + str(x))

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

# Print every animal in animals. This goes through every item in a list and
# puts the value of each item into "animal". The word animal can be anything you
# want, but it makes sense to be animal here.
for animal in animals:
    print(animal)

### 7. Functions ###

# Returns the value of x multiplied by y, with ten added on.
def multiply_numbers_and_add_ten(x, y):
    return (x * y) + 10
    
# Store the value in a variable.
value = multiply_numbers_and_add_ten(5, 10)

# Prints 10
print(value)