locals().update(dictionary) doesn't add all the variables

问题

I have been loading variables using dictionary objects, but the values get updated. What am I missing here?

assert "run_LMM" in all_variables.keys()
locals().update(all_variables)
assert "run_LMM" in locals()

The last line is were I get an assertion error. What's going on?

回答1:

That's the expected behaviour, by the docs:

The contents of this dictionary should not be modified; changes may not affect the values of local and free variables used by the interpreter.

I think, one of the reasons for that is that whether a variable is global or local is defined during the function compilation, so that in:

def func():
    locals()['val'] = 1
    print val

the last statement always reads from the global variable, since the local variable is not declared. So, ability to add locals dynamically would make life harder.

来源：https://stackoverflow.com/questions/24197720/locals-updatedictionary-doesnt-add-all-the-variables