python 类方法（classmethod）小实验代码

class c(object):
foralll = 8
def __init__(self, i, forall):
self.i = i
self.test = 0
self.foralll = forall

print self.i
print self.foralll

def do_print(self):
print "OK"

@classmethod
def do_print_again(clss):
print "OKOK"

@classmethod
def smthd(clss, i, forall):
clss.foralll = forall
print clss.foralll
clss.do_print_again

cc = c(0,0)
cc.do_print()
c.smthd(2, 3)

result：

0
0
OK
OKOK
3

python里面有两个概念，类和实例，凡是def XXX(self)的方法，以及self.XXX的变量都是只能由实例调用的实例就是指代码中的"cc"， 是对类实例化后的结果。而带有@classmethod修饰符的方法，只能调用类中同样由@classmethod修饰符修饰的方法，和在init方法之前声明的那些变量（类变量？）相比较@staticmethod 就不能调用类中的任何值和方法了(二) 一个对比测试

class c(object):
foralll = 8
def __init__(self):
print self.foralll

@classmethod
def smthd(clss, i, forall):
clss.foralll = forall
print clss.foralll

cc = c()
print cc.foralll
c.smthd(2, 3)
print cc.foralll

result:

8833

class c(object):foralll = 8def __init__(self):self.foralll = 0 # differentialprint self.foralll@classmethoddef smthd(clss, i, forall):clss.foralll = forallprint clss.foralllcc = c()print cc.foralllc.smthd(2, 3)print cc.foralll

result:

0030