Python Cheat Sheet

#this is how you maek a list in python

shoppinglist = ['coke zero', 'bacon', 'water', 'jelly', 'gummy bears']

print (shoppinglist)

print (shoppinglist[0])
#prints the first item of the list

list_num = 0

while list_num < len(shoppinglist):
    print ("List:", shoppinglist[list_num])
    list_num =list_num+1
    

#for loop--> same as the above
    #For every item in that list we're going to print it.

for item in shoppinglist:
    print (item)



numbers = range(1,5)
#print up until less then the last number.
for item in numbers:
    print (item)

# a string is a list of characters, letters, numbers, etc.

mystr = "hello"

for letter in mystr:
    print (letter)

mystring = ""
count = 0
while count < 5:
    mystring = mystring + str(count)
    print (mystring)
    count = count + 1

even_value = 0
odd_value = 0
while True:
    user_input = input("Enter a positive number: ")
    number = int(user_input)
    if number < 0:
        print ("There were ", even_value ,"even numbers and there were " , odd_value ,"odd numbers.")
        break
    if number % 2 == 0:
        even_value = even_value + 1
    else:
        odd_value = odd_value +1

def areaofCircle(r):
    if r <= 0:
        return "Error: invalid radius"
    
    pi = 3.1415
    area = pi*(r**2)
    return (area)
user_radius = input('Enter the radius: ')
radius = float(user_radius)
print("The area of the circle is", areaofCircle(radius))

num1= 0
num2=1
mystr = '0'

while num1 + num2 < 89:
    Fibonacci = num1 +num2
    
    num1= num2
    
    num2=Fibonacci
    mystr= mystr+"," + str(num1)
print (mystr) 

def calc(num1, num2, operation):
    
    if operation == "sum":
        return sum(num1, num2)

    elif operation == "product":
        return product(num1, num2)

    elif operation == "diff":
        return diff(num1, num2)

    elif operation == "div":
        return div(num1, num2)

    
def sum(a, b):
    return a+b

def product(a, b):
    return a*b

    
def diff (a, b):
    return a-b
    

    
def div(a, b):
    if b == 0:
        return ("Error")
    elif b != 0:
        return a/b
    

    

print (calc(1,2,"sum"))
print (calc(4,2, "diff"))
print (calc (9,0, "div"))
print (calc (2,12, "product"))

calc(1, 2, "sum")

word = input("Type in an word: ")
reverse = ""
for letter in word:
    reverse = letter + reverse
print ("Reverse: ", reverse)

print(True)
print (2<3)
print (2 != 2)

user_number = input("Please enter a number: ")

number = int(user_number)

countdown_string = ""

while number > 0:
    countdown_string = countdown_string + " " + str(number)
    number = number-1 

print (countdown_string)

def isPalindrome(word):
    
    
    letter_num =0
    while letter_num < len(word)-1-letter_num:
        
        if word[letter_num] == word[len(word)-1-letter_num]:
            letter_num = letter_num +1
            
        else:
            return False
    return True
    
while True:
    user_input = input("Please type in a word: ")
    if user_input == "quit":
        break
    #print (isPalindrome(user_input))
    myvalue = isPalindrome(user_input)
    if myvalue == True:
        print (user_input + " is a palindrome.")
    elif myvalue == False:
        print (user_input + " is not a palindrome.")
    
 


    
    
   
        
    

word = input("Type in an word: ")
reverse = ""
for letter in word:
    reverse = letter + reverse
"""
letter_num = 0

reverse = ''

while letter_num < len(word):
    reverse = (word[letter_num] + reverse)
    letter_num = letter_num + 1
"""

    

print ("Reverse: ", reverse)