 See pages 65 – 67 in your book  While loops are all around us ◦ Shampoo  Rinse, Lather, Repeat  While (Condition Is True) : ◦ Execute a block of code  While loops are controlled by a sentry value

 Make sure the sentry value can evaluate to True, otherwise the while block will never run  Make sure the sentry value can evaluate to False, otherwise the program will never end, resulting in an ‘endless loop’

hungry = True while(hungry == True) : print("Taking a bite") response = input("Still hungry? (y or n)") if (response == "n") : hungry = False print("Well, that was a good hamburger")

secretPassword = “taylorSwift” guessedPassword = “” while (guessedPassword != secretPassword) : guessedPassword = input(“Enter password: ”) if (guessedPassword != secretPassword) : print(“Password incorrect. Try again.”) print(“Password is correct”)

# if statement # if ( ) : # Only executed if condition is true # block A is executed else : # Only executed if condition is false block B is executed # while loop # while ( ) : # Executes over and over as long # as condition evaluates to true block C is executed

# Parent and two-year-old conversation simulator # response = input(“Why won’t you eat your carrots?”) while (response == ‘Because’) : response = input(‘Because why?’) print(‘The real reason: ’, response)

 A ‘for loop’ iterates over a sequence one element at a time  A ‘for loop’ uses uses a variable that gets each successive element of the sequence  Inside the loop body, the loop can then do something with each successive element

 Start with a ‘for’, followed by a variable for each element, followed by ‘in’  Sometimes you need to count. Python provides the range() function for i in range(1, 5) : print(i) Output:

for letter in ‘Python’ : print(letter) Output: P y t h o n

 Write the Python code that uses a while loop to print even numbers between 100 and 200  Now print the even numbers between 100 and 200 using a for loop  Write the Python code that uses a for loop to print each character of “Taylor Swift” on a separate line. Use a for loop