Python基础

目录

一. 基础知识

  1. 变量
  2. 列表
  3. 条件判断
  4. 字典
  5. 函数
  6. 类
  7. 文件
  8. 异常
  9. 测试
  10. 其他

基础知识

1.变量

  1. 字符串

    一些方法

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    msg = "luo jiA  "
    print(msg.title())
    print(msg.upper())
    print(msg.lower())
    print(msg.strip())
    # Luo Jia  
    # LUO JIA  
    # luo jia  
    # luo jiA
    # 可以通过’+‘相连

  2. 数字

    ‘**’ 表示乘方

    str() :强制类型转换

  3. 注释

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# 我是注释

2.列表

注意

存在负数索引方法

增删改

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# 改
moto = ['1', '2', '3']
print(moto)
moto[0] = '0'
moto[1] = '1'
moto[2] = '2'
print(moto)

# 增
moto.append('4')
print(moto)
moto.insert(3, '3')
print(moto)

# 删
del moto[4]
print(moto)
moto.pop()
print(moto)
moto.pop(2)
print(moto)
moto.remove('1')
print(moto)
# ['1', '2', '3']
# ['0', '1', '2']
# ['0', '1', '2', '4']
# ['0', '1', '2', '3', '4']
# ['0', '1', '2', '3']
# ['0', '1', '2']
# ['0', '1']
# ['0']

排序

  1. 永久性排序

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    # 永久排序
    demo = ["a", 'd', 'c', 'e', 'b']
    print(demo)
    demo.sort()
    print(demo)
    demo.sort(reverse=True)
    print(demo)
    # ['a', 'd', 'c', 'e', 'b']
    # ['a', 'b', 'c', 'd', 'e']
    # ['e', 'd', 'c', 'b', 'a']

  2. 临时排序

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    # 临时排序
    demo = ["a", 'd', 'c', 'e', 'b']
    print(demo)
    print(sorted(demo))
    print(sorted(demo, reverse=True))
    print(demo)
    # ['a', 'd', 'c', 'e', 'b']
    # ['a', 'b', 'c', 'd', 'e']
    # ['e', 'd', 'c', 'b', 'a']

  3. 倒序

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    # 倒序
    demo = ["a", 'd', 'c', 'e', 'b']
    print(demo)
    demo.reverse()
    print(demo)
    # ['a', 'd', 'c', 'e', 'b']
    # ['b', 'e', 'c', 'd', 'a']

  4. 定长

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    # 定长
    demo = ["a", 'd', 'c', 'e', 'b']
    print(demo)
    print(len(demo))
    # ['a', 'd', 'c', 'e', 'b']
    # 5

5.遍历

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# 遍历
# for Ldemo in demo:
#     print(Ldemo)
# for num in range(1,5):
#     print(num, end=' ')
# for num in range(1, 11, 2):
#     print(num, end=' ')

6.列表解析

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squares = [value**2 for value in range(1, 11) ]
print(squares)
# [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

7.切片

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# 切片
print(demo)
print(demo[0:len(demo)-1])
print(demo[-3:])
# ['a', 'd', 'c', 'e', 'b']
# ['a', 'd', 'c', 'e']
# ['c', 'e', 'b']

# 利用切片复制列表
demo2 = demo[:]
demo2.pop()
print('demo'+str(demo))
print('demo2'+str(demo2))
# demo['a', 'd', 'c', 'e', 'b']
# demo2['a', 'd', 'c', 'e']
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# # 利用切片复制列表
# demo2 = demo[:]
# demo2.pop()
# print('demo'+str(demo))
# print('demo2'+str(demo2))
# # demo['a', 'd', 'c', 'e', 'b']
# # demo2['a', 'd', 'c', 'e']


# 元组定义和修改
# demo = (1,2)
# print(demo)
# demo = (2,1)
# print(demo)
# (1, 2)
# (2, 1)

3.条件判断

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if a==1:
    print(a)
elif a==2:
    print(a)
else a==3:
    print(a)

4.字典

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# # 字典
# element = {'x': 1, 'y': 2 ,'dict':{'x':1}}
# # 增
# element['z']=3
# print(element)
# # 改
# element['x'] = 4
# print(element)
# # 删
# del element['z']
# print(element)
#
# # 遍历
# for k,v in element.items():
#     print(k+str(v))
#
# for key in element.keys():
#     print(key, end=' ')
# print()
#
# for value in element.values():
#     print(value, end=' ')
# x4
# y2
# dict{'x': 1}
# x y dict
# 4 2 {'x': 1}

5.函数

给参数一个初始值，可以控制传入参数不同时的不同返回结果

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# 函数
def a(f='1', s='', t=''):
    return f + s + t


print(a("luo", 'jia', 'le'))
print(a('jia', 'le'))
print(a())
# luojiale
# jiale
# 1

函数对列表的处理

会直接改变列表

不想改变则传入列表的副本[:]

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a = [11, 12]
b = [13, 15]

def changeList(list):
    list[0]= 1
    list[1]= 2
    print('change-list', list)


print(a)
changeList(a)
print(a)
print(b)
changeList(b[:])
print(b)

# [11, 12]
# change-list [1, 2]
# [1, 2]
# [13, 15]
# change-list [1, 2]
# [13, 15]

传递任意数量的形参

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def make_pizza(*toppings):
    print(toppings)

make_pizza('ljl')
make_pizza('ajl')
# ('ljl',)
# ('ajl',)
# 元组


def make_pizza(*toppings):
    for topping in toppings:
        print(topping)

make_pizza('ljl','ccy')
make_pizza('ajl')
# ljl
# ccy
# ajl

任意数量的关键字实参

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def build_profile(first,sec,**user_info):# 是个字典
    profile={}
    profile['first_name']=first
    profile['sec_name']=sec
    for key,value in user_info.items():
        profile[key] = value
    return profile

user_profile= build_profile('luo','jiale',location='princeton',field='physics')
print(user_profile)
# {'first_name': 'luo', 'sec_name': 'jiale', 'location': 'princeton', 'field': 'physics'}

as的使用

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from XX import XXX as X
import XXX as X

6.类

初始化属性

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class Dog:
    def _init_(self, name):
        self.name=name
      
    def sit(self):
        print(self.name + ' is sitting')

创建实例

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my_dog = Dog('ccy')

my_dog.sit()# ccy is sitting

修改属性

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class Dog():
    def __init__(self, name,age):
        self.name = name
        self.age = age

    def sit(self):
        print(self.name + ' is sitting')

    def happyBirthday(self,year):
        self.age+=year


my_dog = Dog('ccy',1)

print(my_dog.age)
my_dog.happyBirthday(100)
print(my_dog.age)

继承

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class animal():
    def __init__(self, name,age):
        self.name = name
        self.age = age

    def sit(self):
        print(self.name + ' is sitting')

    def happyBirthday(self,year):
        self.age+=year


class Dog(animal):
    # 继承
    def __init__(self, name ,age):
        super().__init__(name,age)
    # 子类方法
    def wolf(self):
        print(self.name + ' : 汪汪汪')
    # 重写
    def sit(self):
        print(self.name +' don\'t care you')


my_dog = Dog('ccy',1)

print(my_dog.age)
my_dog.happyBirthday(100)
print(my_dog.age)
my_dog.wolf()
my_dog.sit()
# 1
# 101
# ccy : 汪汪汪
# ccy don't care you

导入类

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from homework import Restaurant

my_restaurant=Restaurant('luojiale','dish')
my_restaurant.open_restaurant()

@property装饰器

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class Person(object):

    def __init__(self, name, age):
        self._name = name
        self._age = age

    # 访问器 - getter方法
    @property
    def name(self):
        return self._name

    # 访问器 - getter方法
    @property
    def age(self):
        return self._age

    # 修改器 - setter方法
    @age.setter
    def age(self, age):
        self._age = age

    def play(self):
        if self._age <= 16:
            print('%s正在玩飞行棋.' % self._name)
        else:
            print('%s正在玩斗地主.' % self._name)


def main():
    person = Person('王大锤', 12)
    person.play()
    person.age = 22
    person.play()
    # person.name = '白元芳'  # AttributeError: can't set attribute


if __name__ == '__main__':
    main()

7.文件

读取整个文件

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# 123.txt
hello files
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with open('123.txt') as file_object:
    contents = file_object.read()
    print(contents)
# hello files

其他

format

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if __name__ == '__main__':
    # 新建一个列表list，逐个赋值，打印

    # 新建一个列表map，逐个赋值，打印
    map = {}
    map['name'] = "张三"
    map[2] = "男"
    map['studentNo'] = 20000565746

    for key, value in map.items():
        print("{} -> {}".format(key, value))

    for key in map.keys():
        print("{} -> {}".format(key, map.get(key)))
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tag:

    缺失模块。
    1、请确保node版本大于6.2
    2、在博客根目录（注意不是yilia根目录）执行以下命令：
    npm i hexo-generator-json-content --save

    3、在根目录_config.yml里添加配置： 

      jsonContent:
    meta: false
    pages: false
    posts:
      title: true
      date: true
      path: true
      text: false
      raw: false
      content: false
      slug: false
      updated: false
      comments: false
      link: false
      permalink: false
      excerpt: false
      categories: false
      tags: true