Python

Colt Stelle: Notes

Variables

A variable in Python is like a variable in mathematics: it is a named symbol that holds a value.


x = 100
khaleesi_mother_of_dragons = 1
print(khaleesi_mother_of_dragons + x)
101

all, at, once = 5, 10, 15

Naming Restrictions

Python Escape Sequences


Examples 

# Set the message variable equal to any string containing a new-line escape sequence
message = "Hello \n goodbye"
 
# Add a string to the mountains variable that when printed results in: /\/\/\
# You will need to use an escape sequence more than once!
 
mountains = "/\\/\\/\\"
 
 
# Set the quotation variable to any string that contains an escaped double quotation mark
quotation = "My cat said \"meow\""

for `loops`

In Python, for loops are written like this:


for item in iterable_object:
# do something with item

An iterable object is some kind of collection of items, for instance: a list of numbers, a string of characters, a range, etc.

item is a new variable that can be called whatever you want

for `loops` with ranges

Let's print numbers 1 - 7 using our knowledge of looping through ranges.


for number in range(1, 8):
  print(number)

while `loops`

This loop continue to execute while a certain condition is truthy, and will end when they become falsy.


user_response = None
while user_response != "please":
user_response = input("Ah ah ah, you didn't say the magic word: ")

Example: Continues to ask for user input until the user types 'bananas'?


msg = input("whats the secret password?")
while msg != "bananas":
	print("WRONG!")
	msg = input("whats the secret password?")
print("CORRECT!")

# for num in range(1,11):
# 	print(num)

# equivalent of above for loop
num = 1
while num < 11:
	print(num)
	num += 1

# equivalent of above for loop
num = 1
while num < 11:
	print(num)
	num += 1

Example: Print the following beautiful art using both a for loop and a while loop:


😀
😀😀
😀😀😀
😀😀😀😀
😀😀😀😀😀
😀😀😀😀😀😀
😀😀😀😀😀😀😀
😀😀😀😀😀😀😀😀
😀😀😀😀😀😀😀😀😀
😀😀😀😀😀😀😀😀😀😀


# For Loop
for num in range (1, 11):
    print("\U0001f600" * num)

#While Loop 
num = 1
while num < 11:
    print("\U0001f600" * num)
    num += 1

Example : The"Colt talking to his sister"


Hey how's it going? pretty good, you?
pretty good, you?
hahah
hahah
ok very funny
ok very funny
stop copying me
UGH FINE YOU WIN
# repeat everything until the user says "stop copying me"


question = input("Hey how's it going? ")
while question != "stop copying me":
    print (question)
    question = input()
print("UGH FINE YOU WIN")

Example: Guess a number between 1 and 10.


import random

ri = random.randint(1, 10)
attempts = 5

while attempts > 0:
    num = int(input('Guess a number between 1 and 10: '))
    
    if ri > num:
        print('Choose a higher number.')
    elif ri < num:
        print('Choose a lower number.')
    else:
        print('Congratulations! You guessed the right number.')
        break
    
    attempts -= 1
    print(f'You have {attempts} attempts left.')

if attempts == 0:
    print(f'Sorry, you have no more attempts left. The correct number was {ri}.')

Python

Python Escape Sequences

for loops

for loops with ranges

while loops

for `loops`

for `loops` with ranges

while `loops`