What is the Python equivalent of static variables inside a function?

Question

What is the idiomatic Python equivalent of this C/C++ code?

void foo()
{
    static int counter = 0;
    counter++;
          


        

Answer 1

Other answers have demonstrated the way you should do this. Here's a way you shouldn't:

>>> def foo(counter=[0]):
...   counter[0] += 1
...   print("Counter is %i." % counter[0]);
... 
>>> foo()
Counter is 1.
>>> foo()
Counter is 2.
>>> 

Default values are initialized only when the function is first evaluated, not each time it is executed, so you can use a list or any other mutable object to store static values.