If a variable already has a value, how do we change that value later by reassigning a new value?
We can think of variables as being little boxes that are able to store values. In this exercise, we’ve labeled our box
annual_rainfall and put the value of
january_to_june_rainfall in it at first. When we assign a new value in that same variable, the number in our box is replaced by the values for the months from September through December.
In-depth Look at the Exercise
We start with the code below:
january_to_june_rainfall = 1.93 + 0.71 + 3.53 + 3.41 + 3.69 + 4.50 annual_rainfall = january_to_june_rainfall july_rainfall = 1.05 annual_rainfall += july_rainfall august_rainfall = 4.91 annual_rainfall += august_rainfall september_rainfall = 5.16 october_rainfall = 7.20 november_rainfall = 5.06 december_rainfall = 4.06
The very first line of code,
january_to_june_rainfall = 1.93 + 0.71 + 3.53 + 3.41 + 3.69 + 4.50, assigns the result of that addition to the variable named
After that, three examples of using the
+= operator are given to give you an idea of how to update an existing variable’s value,
September through December, then, are the months we haven’t added to the existing variable’s value, which is the goal of the exercise.