eval() and local variables

[Peter Otten]

Peter Luciak wrote:

> Hi,
> I need to do something like this:
> 
> def my():
>         a,b=1,2
>         func = "lambda x: a*x+b"
>         map(eval(func),[1,2,3])
> 
> my()
> 
> NameError: global name 'a' is not defined
> 
> Why do I have to make a,b global for this to work?

You don't: 

>>> def my():
...     a, b = 1, 2
...     return map(eval("lambda x: a*x+b", locals()), [1,2,3])
...
>>> my()
[3, 4, 5]

That makes my's local variables eval's globals. 
However, it's not clear to me why you need eval() at all:

>>> def my():
...     a, b = 1, 2
...     func = lambda x: a*x+b
...     return map(func, [1,2,3])
...
>>> my()
[3, 4, 5]

Peter