Last Key in Python Dictionary

Question

I am having difficulty figuring out what the syntax would be for the last key in a Python dictionary. I know that for a Python list, one may say this to denote the last:

Answer 1

There are absolutely very good reason to want the last key of an OrderedDict. I use an ordered dict to list my users when I edit them. I am using AJAX calls to update user permissions and to add new users. Since the AJAX fires when a permission is checked, I want my new user to stay in the same position in the displayed list (last) for convenience until I reload the page. Each time the script runs, it re-orders the user dictionary.

That's all good, why need the last entry? So that when I'm writing unit tests for my software, I would like to confirm that the user remains in the last position until the page is reloaded.

dict.keys()[-1]

Performs this function perfectly (Python 2.7).

Answer 2

There's a definite need to get the last element of a dictionary, for example to confirm whether the latest element has been appended to the dictionary object or not.

We need to convert the dictionary keys to a list object, and use an index of -1 to print out the last element.

mydict = {'John':'apple','Mat':'orange','Jane':'guava','Kim':'apple','Kate': 'grapes'}

mydict.keys()

output: dict_keys(['John', 'Mat', 'Jane', 'Kim', 'Kate'])

list(mydict.keys())

output: ['John', 'Mat', 'Jane', 'Kim', 'Kate']

list(mydict.keys())[-1]

output: 'Kate'

Answer 3

Since python 3.7 dict always ordered(insert order),

since python 3.8 keys(), values() and items() of dict returns: view that can be reversed:

to get last key:

next(reversed(my_dict.keys()))  

the same apply for values() and items()

PS, to get first key use: next(iter(my_dict.keys()))

Answer 4

In python 3.6 I got the value of last key from the following code

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

Answer 5

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).

Answer 6

yes there is : len(data)-1.

For the first element it´s : 0