the code:
class ceshi():
def one(self):
global a
a = "i m a"
def two(self):
print(a)
if __name__ == '__main__':
ceshi().two()
error message: NameError: name 'a' is not defined
Didn't I define "a"? why the error message is 'name "a" is not defind'
You never actually define a. Just because you have it within function one does not mean that this function will be called.
You should either move a out of the class scope:
a = "i m a"
class ceshi():
def one(self):
# some other code
def two(self):
print(a)
or make a call to one() before calling two(), in order to define a.
if __name__ == '__main__':
ceshi().one()
ceshi().two()
"a" is only defined inside def one(), so you should declare it outside the method scope and later on define its value inside def one() if that's what you want to do. You could just leave it inside def one() but if the method isn't called, it still won't work.
So your code should look like:
class ceshi():
global a
def one(self):
a = "i m a"
def two(self):
print(a)
global a should be moved out of the method into the class?
one() is the problem. Moving the global statement does not help that. Global statements go in a region of local scope to indicate that a referenced variable is global instead of local.
a = somethingwill be defininga. Since you want it to be global it should be outside the class scope.aisn't out of the class. You can perfectly leave it withindef one()and be global, but you also need to actually make a call to functionone(), which you never do.