Accessing dictionary value by index in python

Question

I would like to get the value by key index from a Python dictionary. Is there a way to get it something like this?

dic = {}
value_at_index = dic.ElementAt(index)

where index is an integer

For later visitors of this post: Getting value by index: `dic.values()[index]` Getting key by index: `dic.keys()[index]` — Matthias Herrmann, May 30 '17 at 17:37

score 46 · Accepted Answer · edited Jul 29 '21 at 20:15

46

In Python versions before 3.7 dictionaries were inherently unordered, so what you're asking to do doesn't really make sense.

If you really, really know what you're doing, use

value_at_index = list(dic.values())[index]

Bear in mind that prior to Python 3.7 adding or removing an element can potentially change the index of every other element.

edited Jul 29 '21 at 20:15

amicitas

11,973
4
35
49

answered Feb 27 '13 at 14:43

NPE

464,258
100
912
987

6

Though `OrderedDict` is available if you have the ability to change the original data construction. – Silas Ray Feb 27 '13 at 14:46
>> that adding or removing an element can potentially change the index of every other element. Yes I know that, this is a common sense for many iterators in many languages. – Dmitry Dyachkov Feb 27 '13 at 16:11
Yes, what exactly I want an index for is to get a random values within available key range, just to implement my algorithm. – Dmitry Dyachkov Feb 27 '13 at 16:19
I'm not sure I'd call the value at a given index "random". – MikeRand Feb 27 '13 at 21:59
I could not fit the full reply in here, but check out my answer below that iterates instead of creating a list. It is more accurate than this chosen answer. – user2426679 Jul 24 '15 at 22:43
Doing this sort of thing is useful for inspecting a running program's dictionary when you might not necessarily know a key. i.e dict.values()[0] to see an example of a value. – Craig Brett Aug 25 '16 at 09:40
30

`dic.values()[index]` I obtain 'dict_values' object does not support indexing ..... ? (python 3.6) – B. M. Mar 19 '17 at 08:37
@B.M. you can do what mohammed ali shaik suggests below. – amc Jan 13 '19 at 19:50
1

`TypeError: 'dict_values' object is not subscriptable` – USERNAME GOES HERE Oct 20 '19 at 11:33
`list(dic.values())[index]` works – Carlos Souza Dec 24 '19 at 13:27
This syntax does not work in Python 3.6. Use: value_at_index = list(dic.values())[index] This converts the returned dictionary view to a bona fide list. – Andrew Dec 27 '20 at 16:48

mohammed ali shaik · Answer 2 · 2018-12-26T05:09:09.467

14

Let us take an example of dictionary:

numbers = {'first':0, 'second':1, 'third':3}

When I did

numbers.values()[index]

I got an error:'dict_values' object does not support indexing

When I did

numbers.itervalues()

to iterate and extract the values it is also giving an error:'dict' object has no attribute 'iteritems'

Hence I came up with new way of accessing dictionary elements by index just by converting them to tuples.

tuple(numbers.items())[key_index][value_index]

for example:

tuple(numbers.items())[0][0] gives 'first'

if u want to edit the values or sort the values the tuple object does not allow the item assignment. In this case you can use

list(list(numbers.items())[index])

edited Dec 26 '18 at 05:09

answered Dec 25 '18 at 16:41

mohammed ali shaik

161
1
7

This works perfectly with python 3, thank you! – amc Jan 13 '19 at 19:50
does not work when the index is a string ... `TypeError: list indices must be integers or slices, not str` – Mohd Oct 26 '20 at 10:40

score 10 · Answer 3 · answered Feb 27 '13 at 22:03

10

If you really just want a random value from the available key range, use random.choice on the dictionary's values (converted to list form, if Python 3).

>>> from random import choice
>>> d = {1: 'a', 2: 'b', 3: 'c'}
>>>> choice(list(d.values()))

answered Feb 27 '13 at 22:03

MikeRand

4,550
8
39
61

user2426679 · Answer 4 · 2015-07-24T22:27:31.917

6

While you can do

value = d.values()[index]

It should be faster to do

value = next( v for i, v in enumerate(d.itervalues()) if i == index )

edit: I just timed it using a dict of len 100,000,000 checking for the index at the very end, and the 1st/values() version took 169 seconds whereas the 2nd/next() version took 32 seconds.

Also, note that this assumes that your index is not negative

edited Jul 24 '15 at 22:27

answered Jul 24 '15 at 21:49

user2426679

2,647
1
29
29

Accessing dictionary value by index in python

4 Answers4

Linked