On Wed, Jul 11, 2012 at 02:18:04PM +0530, kala Vinay wrote:
> Hi all,
>
> say i have a string s="['a','b']" and i want to get a list object
> from this string s ie l=['a','b']
The AST module contains a safe way to parse and eval literal
expressions, including strings, nested lists, and builtin constants like
None, True and False.
py> import ast
py> ast.literal_eval('[23, 42, "hello", "world", -1.5, [], {}]')
[23, 42, 'hello', 'world', None, True, False, -1.5, [], {}]
Unlike the eval command, it is safe and won't execute code:
py> text = '__import__("os").system("echo \\"Your computer is mine now!\\"")')
py> eval(text)
Your computer is mine now!
0
py> ast.literal_eval(text)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python2.6/ast.py", line 68, in literal_eval
return _convert(node_or_string)
File "/usr/lib/python2.6/ast.py", line 67, in _convert
raise ValueError('malformed string')
ValueError: malformed string
--
Steven
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