Why does Python let me define a variable in one scope, but use it in another?

Question

I see that it's possible to define a variable inside a scope, but then refer to it outside that scope. For instance, the following code works:

if condition:
    x = 5
else:
    x = 10
print x

However, this strikes me as a bit weird. If you tried to do this in C, the variable X would not be scoped properly:

if(condition) { int x = 5; }
else { int x = 10; }
print x; // Doesn't work: x is unavailable!

The solution, in C anyway, is to declare X first, THEN figure out what do to with it:

int x;
if(condition) { x = 5; }
else { x = 10; }
print x; // Works!

So, in Python, my instinct is to write code like this:

x = None
if condition:
    x = 5
else:
    x = 10
print x

However, I realize Python doesn't require me to do this. Any suggestions? Is there a style guideline for this scenario?

Answer 1

Blocks do not create a new scope in Python. Modules, classes, and functions do.

Also:

x = 10
if condition:
    x = 5
print x

or:

x = 5
if not condition:
    x = 10
print x

Answer 2

My suggestion:

Write Python, not C.

In Python we use blocks. An if is a block. A block doesn't necessarily mean a different scope in Python.