Convert a python dict to a string and back

I am writing a program that stores data in a dictionary object, but this data needs to be saved at some point during the program execution and loaded back into the dictionary object when the program is run again. How would I convert a dictionary object into a string that can be written to a file and loaded back into a dictionary object? This will hopefully support dictionaries containing dictionaries.

Solution 1:

The json module is a good solution here. It has the advantages over pickle that it only produces plain text output, and is cross-platform and cross-version.

import json
json.dumps(dict)

Solution 2:

If your dictionary isn't too big maybe str + eval can do the work:

dict1 = {'one':1, 'two':2, 'three': {'three.1': 3.1, 'three.2': 3.2 }}
str1 = str(dict1)

dict2 = eval(str1)

print dict1==dict2

You can use ast.literal_eval instead of eval for additional security if the source is untrusted.

Solution 3:

I use json:

import json

# convert to string
input = json.dumps({'id': id })

# load to dict
my_dict = json.loads(input)