List user defined variables, python

Question

I am trying to iterate through the variables set in a python script. I came across the following:

Enumerate or list all variables in a program of [your favorite language here]

and in the first example:

#!/us/bin/python                                                                                    

foo1 = "Hello world"
foo2 = "bar"
foo3 = {"1":"a", "2":"b"}
foo4 = "1+1"

for name in dir():
    myvalue = eval(name)
    print name, "is", type(name), "and is equal to ", myvalue

It lists all the variables stored in memory. I want to isolate the variables I have created in my script and not list the system variables created by default. Is there any way to do this?

Answer 1

You can strip out variables that are included in your module by default by checking if they are in the builtin __builtins__ module, like this:

>>> x = 3
>>> set(dir()) - set(dir(__builtins__))
set(['__builtins__', 'x'])

The only thing this doesn't strip out is __builtins__ itself, which is easy to special case.

Also note that this won't work if you have re-defined any builtin names. You shouldn't do this in practice, but a lot of people do, many by accident.