Last Key in Python Dictionary

If insertion order matters, take a look at collections.OrderedDict:

An OrderedDict is a dict that remembers the order that keys were first inserted. If a new entry overwrites an existing entry, the original insertion position is left unchanged. Deleting an entry and reinserting it will move it to the end.

---

In [1]: from collections import OrderedDict

In [2]: od = OrderedDict(zip('bar','foo'))

In [3]: od
Out[3]: OrderedDict([('b', 'f'), ('a', 'o'), ('r', 'o')])

In [4]: od.keys()[-1]
Out[4]: 'r'

In [5]: od.popitem() # also removes the last item
Out[5]: ('r', 'o')

Update:

An OrderedDict is no longer necessary as dictionary keys are officially ordered in insertion order as of Python 3.7 (unofficially in 3.6).

For these recent Python versions, you can instead just use list(my_dict)[-1] or list(my_dict.keys())[-1].

It seems like you want to do that:

dict.keys()[-1]

dict.keys() returns a list of your dictionary's keys. Once you got the list, the -1 index allows you getting the last element of a list.

Since a dictionary is unordered*, it's doesn't make sense to get the last key of your dictionary.

Perhaps you want to sort them before. It would look like that:

sorted(dict.keys())[-1]

Note:

In Python 3, the code is

list(dict)[-1]

*Update:

This is no longer the case. Dictionary keys are officially ordered as of Python 3.7 (and unofficially in 3.6).