20201202-3 局部变量与全局变量作用域-1

1-1
def test4(name,age=9999,*args,**kwargs):
    print(name)
    print(age)
    print(args)
    print(kwargs)
    logger("TEST4")

def logger(source):
    print("from %s" % source)

test4(‘itachi‘,age=21,sex=‘m‘,hobby=‘sweet_rice_ball‘)
--->
itachi
21
()
{‘sex‘: ‘m‘, ‘hobby‘: ‘sweet_rice_ball‘}
from TEST4
运行结果没有问题

1-2 局部变量
def change_name(name):
    print("before change",name)
    name = "Uchiha Itachi"
    print("after change",name)

name = ‘itachi‘
change_name(name)
--->
before change itachi
after change Uchiha Itachi

# 局部变量，只在函数里生效；这个函数就是这个变量的作用域

1-3
school = ‘zxcv edu‘

def change_name(name):
    school = ‘Mage Linux‘
    print(‘before change‘,name,school)
    name = ‘Uchiha Itachi‘
    age = 23
    print(‘after change‘,name)

print(school)
name =‘itachi‘
change_name(name)
print(name)
--->
zxcv edu
before change itachi Mage Linux
after change Uchiha Itachi
itachi

# 全局变量，在函数中是改不了的，函数作用域只在小函数中生效
# 虽然叫同样的名字，但是没关系
# 函数中默认，局部变量无法修改全局变量

1-4 如果想在局部变量中修改全局变量，应该怎么办？ 声明 global
school = ‘zxcv edu‘

def change_name(name):
    global school     # 在函数中修改全局变量
    school = ‘Mage Linux‘
    print(‘before change‘,name,school)
    name = ‘Uchiha Itachi‘
    age = 23
    print(‘after change‘,name)

name =‘itachi‘
change_name(name)
print(name)
print(‘school:‘,school)
--->
before change itachi Mage Linux
after change Uchiha Itachi
itachi
school: Mage Linux

# 这种情况是可以修改的