The Python Apprentice

Merging sequences with zip

The last built-in we'll look at is zip(), which, as its name suggests, gives us a way to synchronise iterations over two iterable series. For example, let's zip together two columns of temperature data, one from Sunday and one from Monday:

>>> sunday = [12, 14, 15, 15, 17, 21, 22, 22, 23, 22, 20, 18]>>> monday = [13, 14, 14, 14, 16, 20, 21, 22, 22, 21, 19, 17]>>> for item in zip(sunday, monday):...     print(item)...(12, 13)(14, 14)(15, 14)(15, 14)(17, 16)(21, 20)(22, 21)(22, 22)(23, 22)(22, 21)(20, 19)(18, 17)

We can see that zip() yields tuples when iterated. This in turn means we can use it with tuple unpacking in the for-loop to calculate the average temperature for each hour on these days:

>>> for sun, mon in zip(sunday, ...