Python “while x:” statement [duplicate]

问题

This question already has answers here:

Python evaluates 0 as False (5 answers)

What is Truthy and Falsy? How is it different from True and False? (5 answers)

Closed 2 years ago.

Why the following while loop is exited when x reaches 0?

x = 1
while x:
    print(x)
    x -= 1

It prints only 1. Shouldn't the while statement be something like: while x "is something": and not just while x:?

回答1:

Because bool(0) => False, and bool(x) for x!=0 => True, so it's like saying while x!=0 or while x>0 in your case.

回答2:

In boolean, none zero value means 'true' and 0 means 'false'. The code reaches the argument while(0) or while(false) and terminate the body

来源：https://stackoverflow.com/questions/46045023/python-while-x-statement