python3 不定长参数传递实例

局部变量

school = 'oldboy edu'
names = ['alex', 'jack', 'rain']
names_tuple = (1,2,3,4)
name = 'alex'
age = 22
# def change_name():
#
#     names[0] = '金角大王'
#     name = '金角大王2'
#     print('inside func', names)
#     print('inside func', name)
#
# change_name()
# print(names)
# print(name)


def change_name2(name):
    global school#修改全局变量
    school = 'mage linux'
    print('before change', name, school)
    name = 'Alex Li'#局部变量作用域
    age = 23
    print('after change', name)


print('school:',school)

name = 'alex'
change_name2(name)
print(name)
print('age:', age)
print('school', school)

参数传入

def test(x,y,z):
    print(x)
    print(y)
    print(z)

# test(y=2,x=1) #与形参顺序无关
# test(1,2)  #与形参一一对应
#test(x=2,3)
test(3,z=2,y=6)

递归

def calc(n):
    print(n)
    if int(n/2)>0:
        return calc(int(n/2))
    print('->',n)

高阶函数

def add(a, b, func):
    return func(a)+func(b)


res = add(1, -6, abs)
#函数位置传入内加求绝对值函数
print(res)

文件操作

import sys

fobj = open('yesterday2', 'r', encoding='utf-8')

fobj_now = open('yesterday2.bak', 'w', encoding='utf-8')

find_str = sys.argv[1]
replace_str = sys.argv[2]

for line in fobj:
    if find_str in line:
        line = line.replace(find_str, replace_str)
    fobj_now.write(line)

fobj.close()
fobj_now.close()

 不定长参数传入

# *args:接收N个位置参数，转换成元组形式

# def test(*args):
#     print(args)
#
# test(1,2,3,4,5)
# test(*[1,2,3,4,5])
# 执行时args = tuple([1,2,3,4,5])

# def test1(x,*args):
#     print(x)
#     print(args)
#
# test1(1,2,3,4,5,6,7)

# **kwargs:接收N个关键字参数，转换成字典方式

# def test2(**kwargs):
#     print(kwargs)
#     print(kwargs['name'])
#     print(kwargs['age'])
#     print(kwargs['sex'])
#
# test2(name='alex', age=8, sex='male')
# test2(**{'name':'alex', 'age':'22', 'sex':'male'})

def test3(name, **kwargs):
    print(name)
    print(kwargs)

test3('alex',age=8, sex='male')

def test4(name, age=18, *args, **kwargs):
    print(name)
    print(age)
    print(args)
    print(kwargs)
    logger('TEST4')

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

test4('alex', age=34, sex='male',hobby='tesla')