Convert a String representation of a Dictionary to a dictionary?

Question

How can I convert the str representation of a dict, such as the following string, into a dict?

s = "{'muffin' : 'lolz', 'foo' : 'kitty'}" 

I prefer not to use eval. What else can I use?

The main reason for this, is one of my coworkers classes he wrote, converts all input into strings. I'm not in the mood to go and modify his classes, to deal with this issue.

Answer 1

You can use the built-in ast.literal_eval:

>>> import ast >>> ast.literal_eval("{'muffin' : 'lolz', 'foo' : 'kitty'}") {'muffin': 'lolz', 'foo': 'kitty'} 

This is safer than using eval. As its own docs say:

 >>> help(ast.literal_eval) Help on function literal_eval in module ast:  literal_eval(node_or_string)     Safely evaluate an expression node or a string containing a Python     expression.  The string or node provided may only consist of the following     Python literal structures: strings, numbers, tuples, lists, dicts, booleans,     and None. 

For example:

>>> eval("shutil.rmtree('mongo')") Traceback (most recent call last):   File "<stdin>", line 1, in <module>   File "<string>", line 1, in <module>   File "/opt/Python-2.6.1/lib/python2.6/shutil.py", line 208, in rmtree     onerror(os.listdir, path, sys.exc_info())   File "/opt/Python-2.6.1/lib/python2.6/shutil.py", line 206, in rmtree     names = os.listdir(path) OSError: [Errno 2] No such file or directory: 'mongo' >>> ast.literal_eval("shutil.rmtree('mongo')") Traceback (most recent call last):   File "<stdin>", line 1, in <module>   File "/opt/Python-2.6.1/lib/python2.6/ast.py", line 68, in literal_eval     return _convert(node_or_string)   File "/opt/Python-2.6.1/lib/python2.6/ast.py", line 67, in _convert     raise ValueError('malformed string') ValueError: malformed string