Python开发基础 day5 函数的定义与使用

#coding:utf-8：

# x=‘你‘ # u‘hello‘

# print(x.encode(‘gbk‘))
# print(b‘\xc4\xe3‘)

# y=b‘\xc4\xe3‘
# print(y.decode(‘gbk‘))

 

 


# x=‘你‘ #unicode.encode(‘utf-8‘)

 

y=u‘你‘
print repr(y)

# while True:
# msg=input(‘>>: ‘)
#
# # print(len(msg))
# # res=len(msg)
# # if res < 5:
# # continue
# # else:break
#
#
# if len(msg) < 5:
# continue
# else:break
#
# with open(‘a.txt‘) as f:
# for i in f.readlines():
# print(i,end=‘‘)

# with open(‘a.txt‘) as f:
# for i in f:
# print(i,end=‘‘)


# with open(‘a.txt‘) as f:
# print(f.readline(),end=‘‘)
# print(f.readline(),end=‘‘)
# print(f.readline(),end=‘‘)
# print(f.readline(),end=‘‘)
# print(f.readline(), end=‘‘)
# print(f.readline(), end=‘‘)


# with open(‘a.txt‘,‘r‘,encoding=‘utf-8‘) as f:
# print(len(f.read()))


# with open(‘a.txt‘,‘rb‘) as f:
# file_size=len(f.read())


# import os
# print(os.path.getsize(‘a.txt‘))

函数参数的使用：


# def foo(x):
# print(x)
#
#
# foo(1)
# foo(‘a‘)
# foo({‘a‘:2})


#形参与实参：
# def foo(x,y): #x=1,y=2
# return x+y
#
# foo(1,2)

 

#===================================part1
#位置参数：按照从左到右的顺序依次定义的参数

def foo(x,y):
print(x)
print(y)
#按位置定义的形参,必须被传值，多一个不行，少一个也不行

# foo(1,2,3)


#按位置定义的实参,与形参一一对应
# foo(2,10)

# def foo(x,y):
# print(x)
# print(y)
#
# # foo(y=10,x=1)
# foo(y=10,x=1) #关键字参数可以不用像位置实参一样与形参一一对应，指名道姓地传值

def foo(x,y):
print(x)
print(y)


# foo(1,10)
# foo(x=1,y=10)
# foo(1,y=10)
# foo(y=10,1)
# foo(x=10,1)

# foo(1,x=10,y=20)


# def foo(x,y,z):
# print(x)
# print(y)
# print(z)
# # foo(1,z=20,10)
# foo(1,y=2,z=10)

# def func(x,y=10):
# print(x)
# print(y)


# func(1,20)
# func(1)

 

# def func(y=10,x):
# print(x)
# print(y)

# def register(name,age,sex=‘male‘):
# print(name,age,sex)
#
# register(‘alex‘,1000)
# register(‘wupeiqi‘,9000)
# register(‘yuanhao‘,10000)
# register(‘王铁蛋‘,10000,‘female‘)

# x=10
# def func(name,age=x):
# print(name)
# print(age)
# x=20
#
# func(‘egon‘)

 

 

# def func(name,age=10,sex=‘male‘,hobby=[‘play1‘,‘play2‘]):
# print(name)
# print(age)
# print(hobby)
#
# func(‘egon‘)

#
# def func(x,y,*args): #x=1,y=2,args=(3,4,5,6)
# print(x,y)
# print(args)
#
# func(1,2,3,4,5,6)

 


# def func(x,y,*args): #args=(3,4,5,6)
# print(x,y)
# print(args)
#
# func(1,2,*(3,4,5,6)) #foo(1,2,3,4,5,6)


# def func(x,y,z):
# print(x,y,z)
#
# # func(1,*(2,3)) #func(1,2,3)
# func(*(2,3)) #func(2,3)

 

#
# def func(x,y=2,z=1):
# print(x,y,z)
#
#
# func(*(‘a‘,‘b‘,‘c‘)) #func(‘a‘,‘b‘,‘c‘)

# def func(x,y,**kwargs): #x=1,y=2,kwargs={‘a‘:1,‘b‘:3,‘z‘:3}
# print(x,y)
# print(kwargs)
#
# func(1,y=2,z=3,a=1,b=3)

 

 

# def func(x,y,**kwargs): #x=1,y=2,**kwargs=**{‘a‘:1,‘b‘:3,‘z‘:3}
# print(x,y)
# print(kwargs)
#
# func(1,y=2,**{‘a‘:1,‘b‘:3,‘z‘:3}) #func(1,y=2,z=3,b=3,a=1)


# def func(x,y=1,z=1):
# print(x,y,z)
#
# func(**{‘y‘:2,‘x‘:1,‘z‘:3}) #

 


# def wrapper(*args,**kwargs): #可以接受任意形式，任意长度的参数
# print(args)
# print(kwargs)
#
#
# wrapper(1,2,3,3,3,3,3,x=1,y=2,z=3)

 


#
# def index(name,group):
# print(‘welcome %s to index page，group is: %s‘ %(name,group))
#
# def wrapper(*args,**kwargs): #可以接受任意形式，任意长度的参数
# # print(args) #args=(1,2,3)
# # print(kwargs) #kwargs={‘x‘:1,‘y‘:2,‘z‘:3}
# index(*args,**kwargs) #index(*(1,2,3),**{‘x‘:1,‘y‘:2,‘z‘:3}) #index(1,2,3,z=3,y=2,x=1)
#
# wrapper(name=‘egon‘,group=‘group1‘)

 

 

 


#命名关键字参数:定义在*后的形参，这类形参，必须被传值，而且要求实参必须是以关键字的形式来传值

# def register(**kwargs):
# print(kwargs)
# if ‘name‘ in kwargs:
# print(kwargs[‘name‘])
# if ‘age‘ in kwargs:
# print(kwargs[‘age‘])
#
#
# # register(name=‘egon‘,age=18)
# register()

 

# def register(*args,name=‘egon‘,age):
# print(args)
# print(name)
# print(age)
#
# # register(name=‘egon‘,age=18)
# register(1,2,2,3,age=10)

 

#
# def register(name,age,*,group,**kwargs):
# print(name)
# print(age)
# print(kwargs)
#
#
# # register(‘egon‘,18)
# register(‘egon1‘,18,hobby=‘paly1‘,group=‘group1‘)


# def func(x,y=1,*args,z,**kwargs):
# print(x)
# print(y)
# print(args)
# print(z)
# print(kwargs)
#
# func(1,2,3,4,5,z=10,a=1,b=2)

 

#
# def func(x,*args,z=1,**kwargs):
# print(x)
# print(args)
# print(z)
# print(kwargs)
#
# func(1,2,3,4,5,a=1,b=2,c=3)

# y=x**2

 

 

 

# def func(x):
# return x**2
# y=func(10) # 10**2
#
# print(y)

 

 

 

# def foo():
# return None
#
# res=foo()
# print(res)

 


# def foo():
# return {‘a‘:1}
#
# res=foo()
# print(res[‘a‘])

 

 

 

# def foo():
# return {‘a‘:1},1,‘a‘,[1,2]
#
# res=foo()
# print(res)

 


‘‘‘
返回值：可以返回任意类型
没有return：None
return value: value
return val1,val2,val3 :(val1,val2,val3)

 


return的效果：只能返回一次值，终止函数的执行
‘‘‘

 


def foo():
return 1
print(‘=====>‘)
return 2
return 3
return 4

 

print(foo())

# print(x) #NameError
# x=1


# func
#
# def func():
# print(‘hello world‘)


 


 


# def func():
# print(‘hello world‘)
#
# # print(func)
# func()


 


 


# def bar():
# print(‘from bar‘)
#
# def foo():
# print(‘from foo‘)
# bar()
#
# foo()


 


# #定义阶段
# def foo():
# print(‘from foo‘)
# bar()
#
# def bar():
# print(‘from bar‘)
#
# #调用阶段
# foo()



#定义阶段:只检测语法，不执行代码
# def func():
# if 1>2
# print(‘hahahahahahah‘)



def func(): #语法没问题，逻辑有问题，引用一个不存在的变量名
asdfasdfasdfasdfasdf


 

#函数是第一类对象： 指的是函数可以被当做数据传递

def func():
print(‘from func‘)

#可被引用
# f=func

#可以当做函数的参数
# def func():
# print(‘from func‘)
# def foo(x):
# print(x)
# x()
#
# foo(func)

#可以当做函数的返回值
# def foo():
# print(‘from foo‘)
# def bar():
# return foo
# f=bar()
# print(f)
# print(foo)

# x=0
# def f1():
# x=1
# def f2():
# # x=2
# print(x)
# return f2
# f=f1()
# # print(f)
# f()

 

#可以当做容器类型的元素
# def select():
# print(‘select function‘)
#
# func_dic={
# ‘select‘:select,
# }
#
# # print(func_dic[‘select‘])
# func_dic[‘select‘]()

 

 


#
# def select():
# print(‘select func‘)
#
# def delete():
# print(‘delete func‘)
#
# def change():
# print(‘change func‘)
#
# def add():
# print(‘add func‘)
#
#
# while 1:
# cmd=input(‘>>: ‘).strip()
# if not cmd:continue
# if cmd == ‘select‘:
# select()
# elif cmd == ‘delete‘:
# delete()
# elif cmd == ‘change‘:
# change()
# elif cmd == ‘add‘:
# add()
# else:
# print(‘无效的命令‘)

 

 

 

def select(cmd_l):
filename=cmd_l[-1]
pattern=cmd_l[1]

with open(filename,‘r‘,encoding=‘utf-8‘) as f:
for line in f:
if pattern in line:
print(line)


def delete():
print(‘delete func‘)

def change():
print(‘change func‘)

def add():
print(‘add func‘)

def check():
print(‘check func‘)


func_dic={
‘select‘:select,
‘delete‘:delete,
‘change‘:change,
‘add‘:add,
‘check‘:check,
}


while 1:
inp=input(‘>>: ‘).strip()
if not inp:continue
cmd_l=inp.split()
# print(cmd_l)
cmd=cmd_l[0]
if cmd in func_dic:
func_dic[cmd](cmd_l)
else:
print(‘无效的命令‘)

#
# def max2(x,y):
# if x > y:
# return x
# else:
# return y
#
# def max4(a,b,c,d):
# res1=max2(a,b) #23
# res2=max2(res1,c) #23
# res3=max2(res2,d) #31
# return res3
#
#
# print(max4(11,23,-7,31))

def f1():
def f2():
def f3():
print(‘from f3‘)
print(‘from f2‘)
f3()
print(‘from f1‘)
f2()
# print(f1)
f1()

‘‘‘
from f1
from f2
from f3

‘‘‘

# x=1
# def func():
# pass
#
# class Foo:
# pass
#
# import os
#
# if 1 > 2 :
# y=3

#局部名称空间:定义在函数内部的名字，局部名称空间只有在调用函数时才会生效，函数调用结束则失效
# def func(x,y): #x=1,y=2
# z=3

# func(1,2)

# # max=10
# def func(): #x=1
# # max=20
# print(max)
#
#
# func()

 

# max=10
#
# def func(): #x=1
# max=20
# # print(max)
# func()
#
#
# print(max)
#


# # x=0
# def f1():
# # x=1
# def f2():
# # x=2
# def f3():
# # x=3
# print(x)
# f3()
# f2()
#
# f1()

# x=1
# def foo():
# def f2():
# print(x)
# f2()
# def bar():
# print(x)
#
# foo()
# bar()


# def f1():
# x=1
# def f2(): #f2=value
# # x=2
# print(x)
# f2()
# f1()


x=1
def func():
x=2
def f1():pass
# print(dir(globals()[‘__builtins__‘])) #全局作用域name
# print(locals()) #局部作用域name

func()

print(globals() is locals())


#局部作用域----->全局作用域