Manual

1a = "test"
2len(a)

 1x = 'hello world'
 2# 分割字符串
 3a = x.split(' ')
 4# ['hello', 'world']
 5
 6# 合并为字符串
 7' '.join(a)
 8# 'hello world'
 9
10
11# 切片
12s = '12 34'
13s[2:4]
14# ' 3'

 1name = "Akvicor"
 2age = 19
 3
 4# print I'm Akvicor
 5new_str = "I'm " + name + ", " + str(age) + " years old"
 6print("Case0: " + new_str)
 7
 8# in python2
 9new_str1 = "I'm %s, %d years old" % (name, age)
10print("Case1: " + new_str1)
11
12# in python3
13new_str2 = "I'm {}, {} years old".format(name, age)
14print("Case2: " + new_str2)
15new_str3 = "I'm {names}, {ages} years old".format(
16    names='Akvicor', ages=age
17)
18print("Case3: " + new_str3)
19new_str4 = f"I'm {name}, {age} years old"
20print("Case4: " + new_str4)
21
22# Case0: I'm Akvicor, 19 years old
23# Case1: I'm Akvicor, 19 years old
24# Case2: I'm Akvicor, 19 years old
25# Case3: I'm Akvicor, 19 years old
26# Case4: I'm Akvicor, 19 years old

1a = None
2a is None
3# True
4
5a = ''
6a is None
7# False

 1a = [1, 2, 3]
 2
 3b = [1, 'abc', 2.0, ['a', 'b', 'c']]
 4
 5print(a)
 6# [1, 2, 3]
 7print(b)
 8# [1, 'abc', 2.0, ['a', 'b', 'c']]
 9print(a[0])
10# 1
11print(a[0], a[1])
12# 1 2
13# 默认两个之间加入空格
14# 默认分隔符为空格，结尾为换行。但可以修改
15print(a[0], a[1], a[2], sep='*', end='-')
161*2*3-
17
18c = b[1:3]
19print(c)
20# ['abc', 2.0]
21s = 'abcdefghijklmn'
22print(s[3:7], s[-5:-2])
23# defg jkl

 1# 获取列表的一些基本信息
 2list1 = [9, 1, -4, 3, 7, 11, 3]
 3
 4print('list1的长度 = ', len(list1))
 5
 6print('list1里的最大值 = ', max(list1))
 7
 8print('list1里的最小值 = ', min(list1))
 9
10print('list1里3这个元素一共出现了{}次'.format(list1.count(3)))
11
12# 列表复制
13list_copy = list1[:]
14# 不能使用 list_copy = list1 这种方法
15# 这只会让list_copy和list1指向同一个列表
16
17# 列表的改变
18list2 = ['a', 'c', 'd']
19print('list2 = ', list2)
20
21# 给list2结尾添加一个元素'e'
22list2.append('e')
23print('list2 = ', list2)
24
25# 在list2的'a'和'b'之间插入一个'b'
26list2.insert(1, 'b')
27print('list2 = ', list2)
28
29# 删除list2里的 'b'  根据值删除元素
30list2.remove('b')
31print('list2 = ', list2)
32
33# 列表反转
34list3 = [1, 2, 3]
35print('list3 = ', list3)
36list3.reverse()
37print('list3 = ', list3)
38
39# 列表排序
40list4 = [9, 1, -4, 3, 7, 11, 3]
41
42# 永久排序
43list4.sort()
44print('list4 = ', list4)
45list4.sort(reverse=True)
46print('list4 = ', list4)
47# 临时排序
48list4Temp = sorted(list4)
49list4Temp = sorted(list4, reverse=True)
50
51# 删除列表元素  根据位置
52list4 = [9, 1, -4, 3, 7, 11, 3]
53# 是用del删除 
54del list4[6]  # -> [9, 1, -4, 3, 7, 11]
55# 是用pop()删除  默认是最后一个元素，也可以是指定元素
56p = list4.pop()  # -> [9, 1, -4, 3, 7, 11]
57# p = 3
58p = list4.pop(0)  # -> [1, -4, 3, 7, 11, 3]
59# p = 9
60
61# ETC
62list5 = [1, 2, 3, 4]
63print(list5 * 2 + [4, 5, 6])
64# [1, 2, 3, 4, 1, 2, 3, 4, 4, 5, 6]

 1list1的长度 =  7
 2list1里的最大值 =  11
 3list1里的最小值 =  -4
 4list1里3这个元素一共出现了2次
 5list2 =  ['a', 'c', 'd']
 6list2 =  ['a', 'c', 'd', 'e']
 7list2 =  ['a', 'b', 'c', 'd', 'e']
 8list2 =  ['a', 'c', 'd', 'e']
 9list3 =  [1, 2, 3]
10list3 =  [3, 2, 1]
11list4 =  [-4, 1, 3, 3, 7, 9, 11]
12list4 =  [11, 9, 7, 3, 3, 1, -4]
13[1, 2, 3, 4, 1, 2, 3, 4, 4, 5, 6]

 1# 元组的创建
 2
 3a = (1, 2, 3)
 4b = 1,
 5print(a, type(a))
 6print(b, type(b))
 7
 8# 元组的访问
 9
10print(a)
11print(a[1])
12print(a[-1])
13print(a[1:3])
14print(a[1:])
15print(a[:2])

 1# 获取元组的一些基本信息
 2tuple1 = (9, 1, -4, 3, 7, 11, 3)
 3
 4print('tuple1的长度 = ', len(tuple1))
 5
 6print('tuple1里的最大值 = ', max(tuple1))
 7
 8print('tuple1里的最小值 = ', min(tuple1))
 9
10print('tuple1里3这个元素一共出现了{}次'.format(tuple1.count(3)))
11
12tuple5 = (1, 2, 3, 4)
13print(tuple5 * 2 + (4, 5, 6))

1tuple1的长度 =  7
2tuple1里的最大值 =  11
3tuple1里的最小值 =  -4
4tuple1里3这个元素一共出现了2次
5(1, 2, 3, 4, 1, 2, 3, 4, 4, 5, 6)

 1# 字典创建
 2
 3a = {
 4    1: 'a',
 5    2: 'b',
 6    '3': 'c'
 7}
 8
 9
10# 不可改变的数据类型
11
12l1 = [1, 2, 3]
13# 因为list是可以改变的，所以下面这种是错误的
14# b = {
15#     l1: 1
16# }
17
18t1 = (1, 2, 3)
19# 这是可以的，因为tuple不可改变
20c = {
21    t1: l1
22}
23print(c)
24
25
26d = dict()
27print(d)
28
29e = dict(a=1, b=2, d='a')
30print(e)
31
32# 字典的访问
33print(e['d'])
34
35e['c'] = 123
36print(e)
37
38e['c'] = 3
39print(e)

1{(1, 2, 3): [1, 2, 3]}
2{}
3{'a': 1, 'b': 2, 'd': 'a'}
4a
5{'a': 1, 'b': 2, 'd': 'a', 'c': 123}
6{'a': 1, 'b': 2, 'd': 'a', 'c': 3}

 1d = {
 2    'Name': 'Jack',
 3    'Age': 9,
 4    'Grade': 5
 5}
 6
 7#  不安全，在没有Name时会报错
 8print(d['Name'])
 9# 在没有Name时输出None
10print(d.get('Name'))
11
12print(d.keys())
13
14print(d.values())
15
16print(d.items())
17
18c = d.pop('Name')
19print(c, d)
20
21d.clear()
22print(d)
23
24
25# 字典的更新
26
27c = {
28    1: 1,
29    2: 2
30}
31print(c)
32c[3] = 3
33c[4] = 4
34
35d = {
36    5: 5,
37    6: 6
38}
39
40# 字典删除  按照键删除
41
42del c[3]
43
44# c.update(d)
45# print(c)
46# 或
47e = {**c, **d}
48print(e)

1Jack
2Jack
3dict_keys(['Name', 'Age', 'Grade'])
4dict_values(['Jack', 9, 5])
5dict_items([('Name', 'Jack'), ('Age', 9), ('Grade', 5)])
6Jack {'Age': 9, 'Grade': 5}
7{}
8{1: 1, 2: 2}
9{1: 1, 2: 2, 3: 3, 4: 4, 5: 5, 6: 6}

 1a = {'f', 'a', 'b', 'c'}
 2
 3print(a)
 4
 5print('c' in a)
 6print('d' in a)
 7
 8li = [1, 2, 3, 2, 4, 5, 2]
 9
10s1 = set(li)
11print(s1, type(s1), list(s1))

1{'a', 'b', 'f', 'c'}
2True
3False
4{1, 2, 3, 4, 5} <class 'set'> [1, 2, 3, 4, 5]

 1s = {1, 2, 3, 4}
 2
 3s.add(5)
 4print(s)
 5
 6# 如果元素不存在会报错
 7s.remove(5)
 8# s.remove(5)
 9print(s)
10
11a = '123452'
12s1 = set(a)
13print(s1)
14
15
16s1 = {1, 2, 3, 4}
17s2 = {3, 4, 5, 6}
18
19print(s1 & s2)
20print(s1 | s2)
21print(s1 ^ s2)
22print(s1 - s2)
23print(s2 - s1)

1{1, 2, 3, 4, 5}
2{1, 2, 3, 4}
3{'2', '4', '3', '5', '1'}
4{3, 4}
5{1, 2, 3, 4, 5, 6}
6{1, 2, 5, 6}
7{1, 2}

1a = eval(input('Please input a integer: '))
2print('Information: ', a, type(a))
3
4if a > 0:
5    print('This integer is large than 0')
6elif a == 0:
7    print('This integer is equal 0')
8else:
9    print('This integer is smaller than 0')

1a = 10
2
3while a > 0:
4    print(a)
5    a -= 1

 1a = '12345'
 2b = [1, 2, 3, 4]
 3c = ('a', 'b', 'c', 'd')
 4d = {
 5    1: 'a',
 6    2: 'b',
 7    3: 'c'
 8}
 9e = {1, 2, 3, 4, 9}
10
11for item in a:
12    print(item)
13
14print('\ndict')
15for item in d:
16    print(item)
17for a, b in d.items():
18    print(f'{a}={b}')
19
20print('\nrange')
21for i in range(1, 20, 3):  # 默认步长等于1,也可以指定步长，例如三
22    # 等价于 C++ 中的 for(int i = 1; i < 20; i+=3)
23    print(i)

 1for i in range(10):
 2    print(i)
 3    if i == 3:
 4        break
 5print('#2')
 6for i in range(10):
 7    if i % 2 == 0:
 8        print(i)
 9print('#3')
10for i in range(10):
11    if i % 2 == 0:
12        continue
13    print(i)

 10
 21
 32
 43
 5#2
 60
 72
 84
 96
108
11#3
121
133
145
157
169

 1import random
 2
 3a = random.randint(0, 100)
 4
 5while True:
 6    num = int(input("Please input your choice: "))
 7    if num == a:
 8        print('\nCongratulation!')
 9        break
10    elif num > a:
11        print('To large')
12    else:
13        print('To small')
14print(f'The number is {a}')

 1
 2def demo():
 3    print('Hello World')
 4    print('demo')
 5
 6
 7demo()
 8
 9
10def demo1(a, b):
11    print(a, b)
12    print('demo1')
13
14
15demo1(a=[1, 2, 3], b={1: 1, 2: 3})
16
17
18def my_sum(a: int, b: int):
19    return a + b
20
21
22print(my_sum(2, 3))
23
24
25def my_max(a):
26    if not a:
27        return None
28    max_value = 0
29    for i in a:
30        if i > max_value:
31            max_value = i
32    return max_value
33
34
35a = [1, 4, 5, 2, 3, 8, 10]
36print(my_max(a))

1Hello World
2demo
3[1, 2, 3] {1: 1, 2: 3}
4demo1
55
610

 1x = 1
 2
 3x += 1
 4
 5print(x)
 6
 7
 8def demo():
 9    x = 10
10    print(x)
11
12
13demo()
14
15print(x)
16
17
18def demo1(a):
19    a = a + 10
20    print(a)
21
22
23demo1(a=x)
24
25print(x)
26
27print("Next")
28y = [1, 2, 3]
29print('This is y', y)
30
31
32def demo2(a):
33    a.append(4)
34    print('demo2', a)
35
36
37def demo22(a):
38    a = a + [4]
39    print('demo22', a)
40
41
42demo22(a=y)
43print('After demo22', y)
44demo2(a=y)
45print('After demo2', y)
46print('可以发现这两种方法中 .append() 会影响原数组，而 + 不会影响')
47
48
49
50z = 1
51print('This is z', z)
52
53
54def demo3(a):
55    global z
56    z = z + a
57    print('In function', z)
58
59
60demo3(a=10)
61print('After Function', z)

 12
 210
 32
 412
 52
 6Next
 7This is y [1, 2, 3]
 8demo22 [1, 2, 3, 4]
 9After demo22 [1, 2, 3]
10demo2 [1, 2, 3, 4]
11After demo2 [1, 2, 3, 4]
12可以发现这两种方法中 .append() 会影响原数组，而 + 不会影响
13This is z 1
14In function 11
15After Function 11

 1def add(a, b):
 2    return a + b
 3
 4
 5print(add(1, 2))
 6
 7
 8def add1(a, b, c):
 9    return a + b + c
10
11
12print(add1(1, 2, 3))
13
14
15def add2(*args):
16    print(args)
17    result = 0
18    for i in args:
19        result += i
20    return result
21
22
23print(add2(1, 2, 3, 4, 5, 6, 7, 8, 9, 10))

13
26
3(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
455

 1def add(**kwargs):
 2    print(kwargs)
 3
 4
 5print(add(a=1, b=2))
 6
 7
 8def test(a, b, c):
 9    print(a + b + c)
10
11
12def add(x, **kwargs):
13    if x == 2:
14        test(**kwargs)
15
16
17add(x=2, a=1, b=2, c=2)

1{'a': 1, 'b': 2}
2None
35

1def test(a, b=False):
2    if b:
3        return a
4    else:
5        return a * a
6
7
8print(test(3))
9print(test(3, True))

19
23

 1def demo(n):
 2    result = 1
 3    for i in range(1, n+1):
 4        result *= i
 5    return result
 6
 7
 8def rec(n):
 9    if n <= 1:
10        return 1
11    return n * rec(n-1)
12
13
14print(rec(5))
15print(demo(5))
16# 120
17# 120

 1class MyClass:
 2    pass
 3
 4
 5# __init__() method 方法 function(函数)
 6# attribute 属性
 7# method 方法
 8
 9
10class People:
11    def __init__(self, name, age):
12        self.name = name
13        self.age = age
14
15    def say_hi(self):
16        print("Hi, my name is {}, and I'm {}".format(self.name, self.age))
17
18
19someone = People('Jack', 20)
20print(someone.name, someone.age)
21someone.say_hi()

 1class People:
 2    def __init__(self, name, age):
 3        self.name = name
 4        self.age = age
 5        self._protect_var = 10  # can be replace
 6        self.__private_var = 10  # can not be replace
 7
 8    def say_hi(self):
 9        print("Hi, my name is {}, and I'm {}".format(self.name, self.age))
10
11    def get_var(self):
12        return self.__private_var
13
14    def set_var(self, var):
15        self.__private_var = var
16
17
18someone = People('Jack', 20)
19someone.say_hi()
20someone.age = 21
21someone.say_hi()
22someone._protect_var = 30
23print(someone._protect_var)
24
25
26print(someone.get_var())
27someone.set_var(30)
28print(someone.get_var())
29
30# python 只是将私有变量改名，并没有阻止我们对他的访问和修改
31# 这只是变相的阻止我们对他的访问，但在实际项目中请不要这样做
32print(dir(someone))
33someone._People_protect_var = 31
34print(someone._People_protect_var)
35someone._People__private_var = 31
36print(someone.get_var())

1Hi, my name is Jack, and I'm 20
2Hi, my name is Jack, and I'm 21
330
410
530
6['_People__private_var', '__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', '_protect_var', 'age', 'get_var', 'name', 'say_hi', 'set_var']
731
831

 1class People:
 2    def __init__(self, name, age, sex):
 3        self.__name = name
 4        self.__age = age
 5        self.__sex = sex
 6
 7    def say_hi(self):
 8        print("Hi, my name is {}, and I'm {}".format(self.__name, self.__age))
 9
10    # def get_name(self):
11    #     return self.__name
12
13    @property
14    def name(self):
15        return self.__name
16
17    def set_name(self, name):
18        self.__name = name
19
20    def get_age(self):
21        return self.__age
22
23    def set_age(self, age):
24        self.__age = age
25
26    # def get_sex(self):
27    #     return self.__sex
28
29    # def set_sex(self, sex):
30    #     self.__sex = sex
31
32    @property
33    def sex(self):
34        return self.__sex
35
36    # 必须设置此变量的property
37    @sex.setter
38    def sex(self, sex):
39        self.__sex = sex
40
41
42someone = People(name='Jack', age=20, sex='Male')
43print(someone.get_age())
44someone.set_age(21)
45print(someone.get_age())
46
47print(someone.name)
48
49someone.sex = 'Female'
50print(someone.sex)

 1class Animal:
 2
 3    def eat(self):
 4        print('Animal is eating')
 5
 6
 7class Bird(Animal):
 8    def sing(self):
 9        print('Bird is singing')
10
11    def eat(self):
12        print('Bird is eating')
13
14
15class Dog(Animal):
16    def eat(self):
17        print('Dog is eating')
18
19
20class Cat(Animal):
21    def eat(self):
22        print('Cat is eating')
23
24
25print('Animal')
26a = Animal()
27a.eat()
28print('Bird')
29b = Bird()
30b.eat()
31b.sing()
32print('Dog')
33d = Dog()
34d.eat()
35print('Cat')
36c = Cat()
37print('This is End\n')
38
39
40def demo_eat(a):
41    a.eat()
42
43
44for i in [a, b, c, d]:
45    demo_eat(i)

 1Animal
 2Animal is eating
 3Bird
 4Bird is eating
 5Bird is singing
 6Dog
 7Dog is eating
 8Cat
 9This is End
10
11Animal is eating
12Bird is eating
13Cat is eating
14Dog is eating

 1class A:
 2    pass
 3
 4
 5class B(A):
 6    pass
 7
 8
 9a = A()
10b = B()
11c = 1
12print('Type A', type(A))
13print('Type B', type(B))
14print('a->A', isinstance(a, A))
15print('c->int', isinstance(c, int))
16print('c->str', isinstance(c, str))
17print('b->B', isinstance(b, B))
18print('b->A', isinstance(b, A))  # 因为B继承自A

 1class Student:
 2    count = 0
 3
 4    def __init__(self, name):
 5        Student.count += 1
 6        self.name = name
 7
 8
 9s1 = Student('A')
10s2 = Student('B')
11s3 = Student('C')
12print(Student.count)
13
14# print(Student.count)
15# # print(Student.name) 必须有实例才能访问
16# s1 = Student(name='A')
17# print(s1.name)
18# print(s1.count)
19#
20# s1.name = 'B'
21# s1.count = 1
22# print(s1.name)
23# print(s1.count)
24# print(Student.count)
25#
26# Student.count = 2
27# s2 = Student(name='C')
28# print('After change')
29# print(Student.count)
30# print(s1.count)
31# print(s2.count)

 10
 2A
 31
 4B
 51
 61
 7After change
 83
 91
103

 1class People:
 2    def __init__(self, name, age):
 3        self.name = name
 4        self.age = age
 5
 6    def sayhi(self):
 7        print(f"Hi, my name is {self.name}, and I'm {self.age}")
 8
 9    @classmethod
10    def test1(cls):
11        print('This is a class method')
12        cls.test2()  # 因为有cls参数，所以可以调用class方法
13
14    @staticmethod
15    def test2():
16        print('This is a static method')
17
18
19p1 = People(name='Jack', age=20)
20p1.sayhi()
21p1.test1()
22p1.test2()
23print('-------------')
24People.test1()
25People.test2()

 1# ch8/demo/math.py
 2def my_sum(*args):
 3    result = 0
 4    for i in args:
 5        result += i
 6    return result
 7
 8
 9def my_max(*args):
10    print("max Value")
11
12
13def my_min(*args):
14    print("min Value")
15
16
17class People:
18    def __init__(self, name, age):
19        self.name = name
20        self.age = age
21
22
23MAX_NUM = 100
24
25
26# print(my_sum(1, 2, 3, 4))

 1# ch8/test.py
 2import sys
 3
 4if '/Users/akvicor/Documents/GitHub/Course/LearnCode/Python' not in sys.path:
 5    sys.path.append('/Users/akvicor/Documents/GitHub/Course/LearnCode/Python')
 6# print(sys.path)
 7
 8from ch8.demo.math import my_sum
 9
10# 只能在pycharm里才不会报错
11# 默认从系统根目录里寻找或从当前目录寻找，pycharm会自动添加ch8设为系统根目录
12print(my_sum(1, 2, 3, 4))

1import sys
2print('Hello World', 'python', sep='%', end='.\n')
3sys.stdout.write('Hello world!\n')
4
5# a = input('ddd: ')
6# print(a, type(a))
7a = sys.stdin.readlines()  # command + D  to stop
8print(a, type(a))

 1f = open("test2.txt", mode='w', encoding='utf8')
 2
 3f.write("line 1\n")
 4f.writelines(['This is second line\n', "line 3\n"])
 5f.write("测试中文")
 6
 7f.close()
 8
 9"""
10参数列表：
11file, mode='r', buffering=None, encoding=None, errors=None, newline=None, closefd=True
12
13    ========= ===============================================================
14    Character Meaning
15    --------- ---------------------------------------------------------------
16    'r'       open for reading (default)
17    'w'       open for writing, truncating the file first
18    'x'       create a new file and open it for writing
19    'a'       open for writing, appending to the end of the file if it exists
20    'b'       binary mode
21    't'       text mode (default)
22    '+'       open a disk file for updating (reading and writing)
23    'U'       universal newline mode (deprecated)
24    ========= ===============================================================
25"""

 1f = open("test2.txt", encoding='utf-8')
 2
 3# a = f.read()  # while read all line from file, and is very slowly
 4# print(a, type(a))
 5
 6# for line in f:  # it will be quickly  # only one times for read
 7#     print(line)
 8
 9a = f.readline()  # while read all line from file, and is very slowly
10b = f.readlines()
11print(a, type(a))
12print(b, type(b))
13
14f.seek(0)  # back to first line
15
16
17f.close()

 1import os
 2
 3os.getcwd()  # 返回一个str，获取当前目录的完整路径
 4
 5os.listdir()  # 返回一个list，包含当前目录里的所有文件和文件夹
 6
 7os.mkdir('demo')  # 创建文件夹
 8
 9os.path.isdir('demo')  # 如果参数是文件夹，返回True
10
11os.chdir('demo')  # 进入一个目录
12
13os.path.exists('demo.txt')  # 当前目录下有没有这个文件夹或者文件，可以是根目录
14
15os.path.join('ch', 'demo.txt')  # 拼接目录，自动添加 '/'

 1import os
 2from pathlib import Path
 3
 4# in_file = os.path.join(os.getcwd(), 'demo', 'test.txt')
 5#
 6# print(in_file)
 7#
 8# a = Path.cwd() / 'demo' / 'test.txt'
 9#
10# print(a)
11# print(type(a))
12#
13# print(a.is_file())
14# print(a.is_dir())
15# print(a.lstat())
16# print(a.parent)
17
18# b = Path.cwd() / 'demo'
19# b = b / 'test'
20# b.rmdir()
21
22p = Path.cwd()
23
24for file in p.glob('*'):
25    print(file)
26
27print('******************************************************************************')
28
29for file in p.rglob('*'):
30    print(file)

 1a = 'hello world'
 2b = b'hello world'
 3
 4type(a)  # <class 'str'>
 5type(b)  # <class 'bytes'>
 6
 7
 8f = open('test3.txt', 'wb')
 9f.write(b'Hello world!')
10f.close()
11
12ff = open('test3.txt', 'rb')
13print(ff.read())
14ff.close()

 1import pickle
 2
 3
 4class People:
 5    def __init__(self, name, age):
 6        self.name = name
 7        self.age = age
 8
 9    def sayhi(self):
10        print("Hi, my name is {}, and I'm {}".format(self.name, self.age))
11
12
13p1 = People(name='Akvicor', age=20)
14f = open('p1', 'wb')
15pickle.dump(p1, f)
16f.close()
17
18
19# 测试序列化对象的加载 （需要类的原型去映射）
20
21fp = open('p1', 'rb')
22p2 = pickle.load(fp)
23f.close()
24print(p2)

1print(sum([1,2,3]))
2b = sum
3print(b([1,2,3]))  # 因为sum是一个函数，所以b被赋值为sum后，b也是个函数，功能与sum相同
4def test(x, f):
5    return f(x)
6printf(test([1,2,3], sum)) # 因为传入的函数为sum， 所以功能为求和
7printf(test([1,2,3], max)) # 因为传入的函数为max， 所以功能为求最大值
8# test就是一个高阶函数

 1def test(x, y):
 2    return x + 2 * y
 3
 4
 5f = lambda x, y: x + 2 * y
 6
 7print(test(1, 2))
 8print(f(1, 2))
 9
10
11def demo(x, y, f):
12    return f(x, y)
13
14
15print(demo(1, 2, lambda x, y: x + 2 * y))
16
17
18def add_n(n):
19    return lambda x: n + x
20
21
22f = add_n(40)
23print(f(1))
24print(f(-10))

1a = [1, 2, 3, 4, 5, 6, 7, 8, 9]
2
3b = [item**2 for item in a if item % 2 == 0]
4
5print(b)
6
7# 列表解析
8
9# 字典解析

 1from functools import reduce
 2
 3a = [1, 2, 3, 4]
 4
 5# def f(x, y):
 6#     return x + y
 7
 8
 9m = map(lambda x: x * x, a)
10
11for i in m:
12    print(i)
13
14
15r = reduce(lambda x, y: x + y, a)
16
17print("r ", r)

 1a = [1, 2, 3, 4, 5, 6, 7, 8, 9]
 2
 3f = filter(lambda x: x % 2 == 1, a)
 4print(f)
 5for i in f:
 6    print(i, end=' ')
 7
 8print("\nlist")
 9
10ff = [i for i in a if i % 2 == 1]
11print(ff)

 1def test1(x):
 2    # print(test1.__name__)
 3    return x * 2
 4
 5
 6def test2(x):
 7    # print(test2.__name__)
 8    return x**3
 9
10
11test1(1)
12test2(2)
13
14
15def demo(f):
16    def f_new(x):
17        print(f.__name__)
18        return f(x)
19    return f_new
20
21
22f = demo(test1)
23
24print(f(3))
25
26
27#  装饰器
28
29@demo
30def test3(x):
31    return x * 2 * x
32
33
34print("for the test3")
35a = test3(4)
36print(a)
37
38
39@demo
40def test3(x):
41    print('hello world')
42
43
44print('After @@')
45test3(1)