Intro to Loops
Loops are repeated programs that you can tell a computer to run. The point of loops is to tell a computer to do something again and again until you achieve a goal. This is called iteration.
While Loops
While Loops are loops that do something while a condition is met, and you can code that something to change again and again until the condition is no longer met.
In general, a while loop follows this basic outline:
while condition: # do stuff # (make sure to have this indented)
For example:
x = 8 while x < 13: print("x is still less than 13") x += 1
View code on GitHub.
The condition for this loop is
x < 13. So, this loop checks if x is less than 13. If it is, then it executes the indented code. It prints “x is still less than 13”. Then, it'll add one to x and repeat the process (check x, print, and add one to x). The loop keeps on going until at one point x is no longer less than 13. In total, it'll print "x is still less than 13" 5 times because that's how many times the computer ran through the loop In the above example, the computer prints when x is 8, 9, 10, 11, and 12. This is why it'll print "x is still less than 13" 5 times
Practice
TV
Pretend you just got a 50 on your test, and your mom says you can't watch TV until you get above an 80. (HINT: use comparison operators). You increase your test score by 10 points per day (iterations). Write a program that tells you how many days you're going to need before you can watch TV.
Up 2 Fifty
Write a program that takes a number from the user and adds 2 to it until it reaches 50 or more, then prints out how many times 2 was added. If the number is already greater than 50, then print out "Already there!"
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