How to get the last number from list in python

Question

Suppose I have the list as

a = [0.0021, 0.12, 0.1224, 0.22]

I have to extract the last number from the above list, so my answer should be 0.22 without using a[3], because the number of the elements in the list always keep changing.

Consider reading about slicing. – devnull Mar 21 '14 at 07:22 — devnull, Mar 21 '14 at 07:22
Will the list ever contain non-numeric values? – Talvalin Mar 21 '14 at 08:17 — Talvalin, Mar 21 '14 at 08:17

msvalkon · Accepted Answer · 2014-03-21T07:27:40.933

7

You're talking about a list. Arrays in python are usually numpy.arrays. They are a completely different data structure.

You can achieve what you want like this:

>>> array = [0.0021, 0.12, 0.1224, 0.22]
>>> array[-1]
0.22
>>>

Negative indexing starts at the end of the list, thus array[-1] will always be the last element in the list, array[-2] the second last and so forth.

edited Mar 21 '14 at 07:27

answered Mar 21 '14 at 07:22

msvalkon

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Please explain a bit more about how the negative indexing works. – thefourtheye Mar 21 '14 at 07:23

score 1 · Answer 2 · answered Mar 21 '14 at 07:24

The appropriate name of [...] is a list. As you know, you can access to an element of a list using an index, like

some_list = [1, 2, 3]
print some_list[0] # first element

But you can also use negative indices:

print some_list[-1] # last element: 3
print some_list[-2] # one before the last element: 2

Note that this will "count" elements from right to left

score 0 · Answer 3 · answered Mar 21 '14 at 07:34

0

Don't worry! Try them!

a[len(a)-1]

or

a[-1]

answered Mar 21 '14 at 07:34

Kei Minagawa

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How to get the last number from list in python

3 Answers3