Scoping in Python 'for' loops

Question

I\'m not asking about Python\'s scoping rules; I understand generally how scoping works in Python for loops. My question is why the design decisions were m

Answer 1

For starters, if variables were local to loops, those loops would be useless for most real-world programming.

In the current situation:

# Sum the values 0..9
total = 0
for foo in xrange(10):
    total = total + foo
print total

yields 45. Now, consider how assignment works in Python. If loop variables were strictly local:

# Sum the values 0..9?
total = 0
for foo in xrange(10):
    # Create a new integer object with value "total + foo" and bind it to a new
    # loop-local variable named "total".
    total = total + foo
print total

yields 0, because total inside the loop after the assignment is not the same variable as total outside the loop. This would not be optimal or expected behavior.