How is correct use of eval()
Nobody
nobody at nowhere.com
Mon Oct 11 21:35:28 EDT 2010
On Tue, 12 Oct 2010 01:26:25 +0100, Nobody wrote:
>>> What is correct way to use this function?
>>
>> To not use it in the first place if at all possible (use int(),
>> float(), getattr(), etc. instead,
>
> Use read(). Oh wait, Python doesn't have that. Because parsing literals
> and executing code are like totally the same thing.
Oh, look what's "new in version 2.6":
> ast.literal_eval("7")
7
> ast.literal_eval("7") == 7
True
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.
This can be used for safely evaluating strings containing Python
expressions from untrusted sources without the need to parse the
values oneself.
I'm guessing that I'm not the only person who hasn't noticed this until
now.
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