Page 64 -

starting to code

Python’s while loop

Programming languages have lots of different ways of creating loops,
but one of the simplest ways in Python is to use a while loop. Here’s
an example:
We want to make The loop body is the
sure the loop runs
the first time. The loop condition the “while” line.
indented code following
answer = "no"
while answer == "no":
answer = input("Are we there? ")
The loop body is just one line of code
print("We're there!")
in this example, but the loop body can
include branches and other loops.
This is what the loop looks like when you write it as a Python while loop. be many lines of code. It might even
The code keeps asking the question “Are we there?” until the user types
something other than no. This is what it looks like when it runs:

As soon as we type something
other than “no", the loop
body ends.

Did you notice that you had to set the value of the answer variable to
something sensible before you started the loop? This is important, because
if the answer variable doesn’t already have the value no, the loop
condition would have been false and the code in the loop body would
never have run at all.
Bear that in mind. It might be useful in this next exercise...

you are here 4 29