Python modify dictionary names iterate

Question

If I have a dictionary like this below:

test = {'1629417600000': {'Payload': 1},
         '1629418500000': {'Payload': 2},
         '1629419400000': {'Payload': 3},
         '1629420300000': {'Payload': 4},
         '1629421200000': {'Payload': 5},
         '1629422100000': {'Payload': 6},
         '1629423000000': {'Payload': 7},
         '1629423900000': {'Payload': 8},
         '1629424800000': {'Payload': 9},
         '1629425700000': {'Payload': 10}}

How can I modify the dictionary key names? I am trying to keep the same name but divide as a float by 1000.

This will throw an RuntimeError: dictionary keys changed during iteration below. Any tips greatly appreciated.

for key in test.keys():
    test[str((float(key)/1000))] = test.pop(key)

Does this answer your question? [Change the name of a key in dictionary](https://stackoverflow.com/questions/4406501/change-the-name-of-a-key-in-dictionary) — Mohammad, Aug 21 '21 at 19:49
Its unix time. Maybe int is what I need not float. Would you have a tip on how to create a new dictionary? — bbartling, Aug 21 '21 at 19:49
When you iterating a list or dictionary, you can not change it, because your are iterating it. if you want to change anything such as key, you have to create a temp list of keys that you want to change. In your example, instead of pop. you have to save them in another list and after for loop ended, change items. good lock — Reza Akraminejad, Aug 21 '21 at 19:49

Z Che · Answer 1 · 2021-08-21T19:57:12.677

3

Try this?

test = {key.removesuffix("000"): value for key, value in test.items()}

However note that this does not modify test in-place, but rather creates a new dictionary, and then assign the new dictionary to test.

Alternatively, a minor change to your original code would fix it:

for key in list(test.keys()):
    test[str((float(key)/1000))] = test.pop(key)

This works because the list(test.keys()), that is being iterated, does not change during the iteration since it is created before the iteration starts and does not depend on the change of test later on.

edited Aug 21 '21 at 19:57

answered Aug 21 '21 at 19:54

Z Che

69
3

3

You can just use `list(test)` – juanpa.arrivillaga Aug 21 '21 at 19:56

score 1 · Accepted Answer · answered Aug 21 '21 at 19:50

1

You can use a dictionary comprehension to create a new dictionary with the updated keys you desire:

test = {str(int(k) // 1000): v for k, v in test.items()}

answered Aug 21 '21 at 19:50

Zachary Cross

2,298
1
15
22

1

You can slice 3 last chars from string instead of conversion `test = [k[:-3]: v for k, v in test.items()}` – Olvin Roght Aug 21 '21 at 19:53
1

Why not use a substring instead of double conversion – Musa Aug 21 '21 at 19:53
@Musa would work too, note, python doesn't have a `double` type. Only a single `int` type – juanpa.arrivillaga Aug 21 '21 at 19:58
I meant converting twice, string to int then int to string – Musa Aug 21 '21 at 19:59

score 0 · Answer 3 · answered Aug 21 '21 at 19:55

0

try with this:

for key in list(test.keys()):

    test[str((float(key)/1000))] = test.pop(key)

answered Aug 21 '21 at 19:55

Piero

404
3
7
22

Python modify dictionary names iterate

3 Answers3