python cheat sheet - ToeyD

while True: # forever
    user_input = input('Enter a number: ')
    number = int(user_input)
    print ('The number squared is', number ** 2)

count = 0 # start at zero
while count < 10: # loop while count is less than 10
    print(count) #will print numbers 0 - 9
    count = count + 1 # must increase count

mylist = [2,3,4,5] # create a list

#select an item from a list
print (mylist[0]) #selects first item and displays 2

# len() determines the length of the list
print (len(mylist)) # displays 4

mylist.append(5) # adds an item to the end of the list

while True:
    

#get a number from the user
    user_number = input("Please enter a number: ")


    #convert to integer
    number = int(user_number)

    hex_string = ''
    while (number > 0):#the number is greater than 0)
        remainder = number % 16 #use Modulo %
        if remainder == 10:
            remainder = 'A'
        elif remainder == 11:
            remainder = 'B'
        elif remainder == 12:
            remainder = 'C'
        elif remainder == 13:
            remainder = 'D'
        elif remainder == 14:
            remainder = 'E'
        elif remainder == 15:
            remainder = 'F'


        hex_string = str(remainder) + hex_string #remainder + hex string
        number = number // 16#must use // when you divide

    #after the loop print the hex string
    print ("Hexadecimal string is 0x" + hex_string)

    #expected output - 5 = 101
    #excepted output - 3 = 11
    #excepted output - 2 = 10

# how to create a function

def nameOfFunction (myvar1, myvar2): # parameters or argu ments
    print ("hello")  #must indent each line that is part of the function

    return myvar1 + myvar2

# function call

nameOfFunction ('hi', 'there')  # a value for each argument


#write a function

# name : areaOfTriangle
# parameters : base height
# return : area

def areaOfTriangle (base, height):
     area = 0.5\*base\*height
     return area

if 3 < 2: #if statement must compare two Booleans
    print ('3 is less than 2')
elif 4 < 2: #can have 0 or more elif statements
    print ('4 is less than 2')
elif 5 < 2:
    print ('5 is less than 2')
else: #can have 0 or 1 else statement at the end
    print ('none of the above are True')