Python turns strings into tuples after assigned to dictionary

Question

I have a really weird python problem. I have already asked several colleagues who all had no idea how it happened and how it could be solved.

I have a shallow dict of strings that I receive from an API call and I want to assign some of those values to a new dict.

This is what the first dict looks like. Just a bunch of strings:

I assign some values from dict1 to some keys in dict2. Really basic

    dict2={}
    dict2['access_key'] = dict1['access_key']
    dict2['secret_access_key'] = dict1['secret_access_key'],
    dict2['session_token'] =dict1['session_token'],
    dict2['region'] = dict1['region']

Then this happens. The values for "secret access key" and "session_token" are turned into tuples. "access_key" and "region" remain strings

I have already tried initialising the values as strings, accessing the first entry of the tuple and casting the value to a string. All of that did not change anything. It seems like the value is assigned just fine and then something weird happens that turns it into a tuple

This is a screenshot of my Interpreter settings. I am using Pyython 3.6

I am really going crazy over this one :-/ Any help would be greatly appreciated

Remove the commas at the end of your lines. Commas make things into tuples. — khelwood, Nov 19 '18 at 07:16
Why do you have commas at the end of some lines where you copy over to dict2? Commas are used to define tuples in Python, could you check that part? — crazyGamer, Nov 19 '18 at 07:18
Probably a copy/paste error where you've left commas on the end of the line. I've been coding in Python for I don't know how long, perhaps 20 years, and still very occasionally make the mistake, and I end up in the debugger trying to work out what I've done. — Peter Wood, Nov 19 '18 at 07:21

score 50 · Accepted Answer · answered Nov 19 '18 at 07:17

50

You have trailing commas at the end of two of your calls. This is why the strings are transformed to tuples.

answered Nov 19 '18 at 07:17

Patol75

4,342
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17
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3

You are absolutely right :-D Thank you very much. Damn those monday mornings – Maximilian Jesch Nov 19 '18 at 07:23
1

I had the same issue and this answer helped me too. My hero! – Insacuri Jun 18 '20 at 16:01
Great catch!! Thanks :) – Gambit1614 Sep 03 '21 at 09:35
Amazing, thanks! – k-war Dec 02 '21 at 22:21

score 8 · Answer 2 · answered Nov 19 '18 at 07:40

My dear friend , the reason you have this problem is in Python tuple is idetified by commas.

You can try this code

a = 1, 
print(a,type(a))
b = 1
print(b,type(b))

So I update your code to this:

dict2={}
dict2['access_key'] = dict1['access_key']
# please notes the end !
# dict2['secret_access_key'] = dict1['secret_access_key'],
# dict2['session_token'] =dict1['session_token'],
# above is the origin code
dict2['secret_access_key'] = dict1['secret_access_key']
dict2['session_token'] =dict1['session_token']
dict2['region'] = dict1['region']

I think this will help!

Nikhil Mohan · Answer 3 · 2018-11-19T09:36:18.000

2

Try the following by removing the trailing commas:

dict2={}
dict2['access_key'] = dict1['access_key']
dict2['secret_access_key'] = dict1['secret_access_key']
dict2['session_token'] =dict1['session_token']
dict2['region'] = dict1['region']

edited Nov 19 '18 at 09:36

answered Nov 19 '18 at 07:19

Nikhil Mohan

118
4

That code looks exactly the same as the problem code. – Peter Wood Nov 19 '18 at 07:27
1

please look at the trailing commas in the question. That is the issue. – Nikhil Mohan Nov 19 '18 at 07:32
1

Your answer should make that obvious. – Peter Wood Nov 19 '18 at 07:36

Python turns strings into tuples after assigned to dictionary

3 Answers3