Getting the last element of a list
some_list[-1]
is the shortest and most Pythonic.
In fact, you can do much more with this syntax. The some_list[-n]
syntax gets the nth-to-last element. So some_list[-1]
gets the last element, some_list[-2]
gets the second to last, etc, all the way down to some_list[-len(some_list)]
, which gives you the first element.
You can also set list elements in this way. For instance:
>>> some_list = [1, 2, 3]
>>> some_list[-1] = 5 # Set the last element
>>> some_list[-2] = 3 # Set the second to last element
>>> some_list
[1, 3, 5]
Note that getting a list item by index will raise an IndexError
if the expected item doesn't exist. This means that some_list[-1]
will raise an exception if some_list
is empty, because an empty list can't have a last element.
If your str()
or list()
objects might end up being empty as so: astr = ''
or alist = []
, then you might want to use alist[-1:]
instead of alist[-1]
for object "sameness".
The significance of this is:
alist = []
alist[-1] # will generate an IndexError exception whereas
alist[-1:] # will return an empty list
astr = ''
astr[-1] # will generate an IndexError exception whereas
astr[-1:] # will return an empty str
Where the distinction being made is that returning an empty list object or empty str object is more "last element"-like then an exception object.
You can also do:
alist.pop()
It depends on what you want to do with your list because the pop()
method will delete the last element.