Solutions

A range of possiblities

1. This does exactly what our first range command did, we have just specified the default values, start=0 and step=1.
2. This steps through the even integers.
3. This returns an empty list because there are no number starting at 10 that are smaller than 0.
4. Because step=-2 the order of the range is reversed, so it produces the list of numbers greater than stop.
5. range takes only integer values so this raises a TypeError: 'float' object cannot be interpreted as an integer.

Looping over a list

In the first example of a loop we assigned a list to numbers and used this as the collection of values to loop over. We can do exactly the same here. In order to avoid using len we also need to increment a counter:

pressures = [0.273, 0.275, 0.277, 0.275, 0.276]
sum_pressures = 0.0
num_pressures = 0
for pressure in pressures:
    sum_pressures += pressure
    num_pressures += 1

mean_pressure = sum_pressures / num_pressures
print("The mean pressure is:", mean_pressure)

Generally this would be considered more "pythonic" than the previous example, because it is more readable. 'For each index in a range the length of the list pressures ...' is not as readable as 'For each pressure in the list of pressures ...'. We have also introduced the accumulator operator value += new_value. This is the same as writing value = value + new_value but is shorter and easier to read.

Looping over a string

string = "Hello world!"
for ch in string:
    print(ch)

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