how to avoid eval in python for string conversion?

Question

I'm confronted with an "eval" problem and I would like your advice, I know eval is wrong and I wish to avoid it but I don't know how...

I have some python objects stored in a database, they are stored as strings and I transform them into actual objects with eval. As an example, my objects could be some simple strings like "[2,1,3,4]" or "[[None,None],None]" -- they correspond to different types of object, they don't follow a common pattern. I have to store them as human-readable objects as they are now.

My problem is how to avoid eval in this case ? I don't want to write a parser for each object.

If I do have to use eval, how do I clean up these strings so that they don't do anything nasty ?

Where did these strings come from? Have you considered creating them using pickle or json? — Wooble
– Wooble, Commented Mar 1, 2013 at 14:23

Pavel Anossov · Accepted Answer · 2013-03-01 14:23:38Z

4

Use ast.literal_eval:

In [9]: import ast
In [10]: ast.literal_eval("[2,1,3,4]")
Out[10]: [2, 1, 3, 4]

answered Mar 1, 2013 at 14:23

Pavel Anossov

63.3k16 gold badges156 silver badges125 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

how to avoid eval in python for string conversion?

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related