### Question

In this exercise, the function written computes the average of two numbers passed as parameters. If the function were given a list of numbers, how could the average be calculated?

### Answer

There are several ways to write a function to calculate the average of a list. In later versions of Python 3, there is a `statistics`

library which contains a `mean()`

function that can perform the calculation directly. Another simple way is to use the `sum()`

and `len()`

functions as shown below. Python 2 does not perform division using floating point unless instructed to do so by being given a floating point number (Python 3 does the conversion automatically) so the sum is cast to floating point.

```
def avg(numbers):
return float(sum(numbers))/len(numbers)
```

Finally, it can be done using a `for`

loop and variables to store the sum and length. This is more involved than the previous version but achieves the same result.

```
def avg(numbers):
sum = 0
count = 0
for n in numbers:
sum += n
count += 1
return float(sum) / count
```