16.2. Iterating Parts of a List¶
Recall that the
range function has a version that looks like:
range(start, end, change).
It produces a sequence that begins with the
start value, increases by
change at each step,
and stops when it hits
end (but will not include the
We can use that to do things like iterating through every other item in a list. This program does exactly that by starting from 0 and using a change value of 2. This means it visits indexes 0, 2, 4…
Or maybe we want to only iterate through half of the list. We can specify a range that does
not start at 0 and end at
The current code loops through just the first half of the list. It calculates half of
the length of the list and uses that as the
end value in the range function call.
If the list length was 5, we would not want to call the halfway point 2.5 There is no
index 2.5 in a list! So when calculating half the length we will use integer division
//) to make sure we get a whole number answer.
Modify the code to loop through just the second half of the list.