python can declare global variable in local scope?

Question

python can declare global variable in local scope?

It works:

def main():
    # do some... for files varible
    for file in files:
       result = func(file)
    print result

I can't understand. Somebody tell me why result can be seen outside the for loop.

Thanks you.

Answer 1

for statements do not start a new scope. Only modules, class declarations, and function definitions start a new scope.

Answer 2

I don't see a global variable declaration. result is a local variable, as is file . Are you talking about files ? That looks like a global variable, but I don't see it declared locally.

Update based on @DSM's helpful comment:

If you are talking about result as being declared locally inside the for -loop, it doesn't work that way in Python, the for -loop doesn't create a local scope.

Answer 3

If you a function uses assignment = or augemnted assignemnt (ie += ) then the variable is considered local by default. However, if you want to make the assignments global use the global keyword.

foo = 2
def bar():
    foo = 3 # foo is locally defined here

def car():
    global foo
    foo = 4 # foo is globally reassigned here

bar() # foo is still 2
car() # foo is now 4