parsing string to a dict [duplicate]

Question

This question already has answers here:

Convert a String representation of a Dictionary to a dictionary (13 answers)

Closed 12 years ago.

I have a string output which is in form of a dict ex.

{'key1':'value1','key2':'value2'} 

how can make easily save it as a dict and not as a string?

• Dave: This was answered quite well in previous question 988228
• S.Lott: What? Why not save the dict as a dict instead of creating a string in the first place? Please provide some more context on this. The question makes very little sense and indicated far larger and deeper problems may have lead to this.
• dbr: As pointed out by Dave, stackoverflow.com/questions/988228/… is an exact duplicate of this

Answer 1

astr is a string which is "in the form of a dict". ast.literal_eval converts it to a python dict object.

In [110]: import ast
In [111]: astr="{'key1':'value1','key2':'value2'}"
In [113]: ast.literal_eval(astr)
Out[113]: {'key1': 'value1', 'key2': 'value2'}

• Robert Rossney: Note that this using eval is not such a good idea if there's any way astr can contain, say, os.remove("foo").

Answer 2

This is best if you're on Python 2.6+, as it's not subject to the security holes in eval.

import ast
s = """{'key1':'value1','key2':'value2'}"""
d = ast.literal_eval(s)

• Chris Lutz: You messed up the quotes. Use double quotes for the outside ones.

Answer 3

Where are you getting this string from? Is it in JSON format? or python dictionary format? or just some ad-hoc format that happens to be similar to python dictionaries?

If it's JSON, or if it's only a dict, and only contains strings and/or numbers, you can use json.loads, it's the most safe option as it simply can't parse python code.

This approach has some shortcomings though, if for instance, the strings are enclosed in single quotes ' instead of double quotes ", not to mention that it only parses json objects/arrays, which only coincidentally happen to share similar syntax with pythons dicts/arrays.

Though I think it's likely the string you're getting is intended to be in JSON format. I make this assumption because it's a common format for data exchange.

Answer 4

using json.loads - may be faster

• Ed Avis: json.loads works well for parsing JSON, but Python dictionary syntax is not quite the same. Even if you only handle simple cases, one difference is that JSON strings have to be "" quoted, while Python allows '' quotes, as in the example given.