Converting string to dictionary python

Question

I created a file and there is a dictionary. Now I want that dictionary from the file but I do not want in string and I don't want the newline character. I obtained something like this:

"{'Greennhouse 1': {'Product': '4', 'Location of greenhouse': '2',
'Unities of the product': 6, 'Designation': '1', 'Growth state of the
product': '5', 'Code of wsn': 1, 'Area of greenhouse': 3}}\n"

But I want this:

{'Greennhouse 1': {'Product': '4', 'Location of greenhouse': '2',
'Unities of the product': 6, 'Designation': '1', 'Growth state of the
product': '5', 'Code of wsn': 1, 'Area of greenhouse': 3}}

Have a look at this: http://stackoverflow.com/questions/988228/converting-a-string-to-dictionary — Saicharan S M, Apr 29 '15 at 22:11
I try using dict, with something I saw here, but it didn't work, because I have a dictionary in another dictionary, I guess. I thought of creating a new dictionary and putting the elements there, but I don't now how to take the str... — Diana Vasconcelos Ferreira, Apr 29 '15 at 22:12
Given the description in the question, [`ast.literal_eval`](https://docs.python.org/2/library/ast.html#ast.literal_eval)is clearly the way to go. — Sylvain Leroux, Apr 29 '15 at 22:13
@SaicharanSM I actually have seen that, but I wanted to avoid any other imports (because I already have a lot). — Diana Vasconcelos Ferreira, Apr 29 '15 at 22:23
@SylvainLeroux I will probably use that, but do I have to import ast? — Diana Vasconcelos Ferreira, Apr 29 '15 at 22:24
@Diana `ast` is a standard module -- it should be available on any (decently recent) standard installation of Python. You only have to add `import ast` to use it. — Sylvain Leroux, Apr 29 '15 at 22:47

Greg Hewgill · Answer 1 · 2015-04-29T22:28:38.380

4

The ast.literal_eval function is designed to convert Python literal expressions represented as a string, into actual Python data structures. So:

import ast

dictionary = ast.literal_eval(string)

The presence of the \n newline character in the input will be of no consequence.

edited Apr 29 '15 at 22:28

answered Apr 29 '15 at 22:15

Greg Hewgill

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I use that and it worked. But now I can't get values from the dictionary... What should I do? I already try by creating a new dictionary, using the get(), but nothing works... – Diana Vasconcelos Ferreira Apr 29 '15 at 22:55
@DianaVasconcelosFerreira: It's unclear what you mean by "it worked" and then you say that you can't get values from the dictionary. If you continue to have trouble, I suggest opening a new question for the next problem you encounter. – Greg Hewgill Apr 30 '15 at 02:45

Jose Ricardo Bustos M. · Answer 2 · 2015-04-30T10:51:33.757

0

although better ast.literal_eval use, depending on the circumstances may be used exec, who interprete all code into a string

s = "{'Greennhouse 1': {'Product': '4', 'Location of greenhouse': '2', 'Unities of the product': 6, 'Designation': '1', 'Growth state of the product': '5', 'Code of wsn': 1, 'Area of greenhouse': 3}}\n"
s = "d=" + s
exec s
print d

edited Apr 30 '15 at 10:51

answered Apr 29 '15 at 22:12

Jose Ricardo Bustos M.

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Using `exec` is terrible advice here. – Greg Hewgill Apr 29 '15 at 22:14
@GregHewgill why? could you tell me why ? – Jose Ricardo Bustos M. Apr 29 '15 at 22:17
1

(1) Using `exec` exposes your code to injection or DoS attacks when the input is from some external source. (2) Using `exec` requires another variable (`d`) which even using the general `eval` would avoid. (3) Using `exec` within a function can severely impact the performance, because its presence disables many optimisations that the compiler can do. – Greg Hewgill Apr 29 '15 at 22:20
@GregHewgill (1) it depends on the use of the script if it is for personal use there is no problem, sometimes don't be paranoid (2) why? do not give a reason (3) this is true, but sometimes the performance isn't the most important ..... – Jose Ricardo Bustos M. Apr 29 '15 at 22:27
(4) There is a much better alternative for this purpose (`ast.literal_eval`). – Greg Hewgill Apr 29 '15 at 22:28
@GregHewgill (4) you are right .... is better `ast.literal_eval` .... but .... it isn't my answer "terrible advice" – Jose Ricardo Bustos M. Apr 29 '15 at 22:29
Then I would suggest changing "should" in your answer to "can". There is no reason to choose `exec` over any of the other choices presented in the answers here. – Greg Hewgill Apr 29 '15 at 22:30
@GregHewgill you are right .... english problem .... I confuse may, can , could, might, and must ..... in my native language they are similar – Jose Ricardo Bustos M. Apr 29 '15 at 22:35
No worries. I'll remove my downvote. – Greg Hewgill Apr 29 '15 at 22:36
Although the code is appreciated, it should always have an accompanying explanation. This doesn't have to be long but it is expected. – peterh Apr 30 '15 at 03:49
@peterh done, add better explanation – Jose Ricardo Bustos M. Apr 30 '15 at 10:52

score 0 · Answer 3 · answered Apr 29 '15 at 22:25

to get your dictionnary from a file as the way you want you have to save it like an object you can use pickle from python standard library

import pickle
mydic = {'Greennhouse 1': {'Product': '4', 'Location of greenhouse': '2',
       'Unities of the product': 6, 'Designation': '1', 'Growth state of the
        product': '5', 'Code of wsn': 1, 'Area of greenhouse': 3}}
with open("mydic.dic","wb") as f :
    pickle.dump(mydic,f)
# later in code
with open("mydic.dic","rb") as f :
    mynewdic = pickle.load(f)
    print mynewdic

Converting string to dictionary python

3 Answers3