15、三元表达式、内置函数和模块基础

一、三元表达式

​
# def func(x,y):
#     if x > y:
#         return x
#     else:
#         return y
#
# res = func(1,2)
​
x = 1
y = 2
​
res = 'ok' if x > y else 'no'  # 条件?值1:值2
print(res)
​
​
​
​

 

二、内置函数

# max
# min
# sorted
​
​
# filter
# names = ['egon','liusir_dsb',"housir_dsb"]
#
# print([name for name in names if name.endswith('dsb')])
#
# res = filter(lambda name:name.endswith('dsb'),names)
# # print(res)
# print(list(res))
​
​
# map
# names = ['lxx', 'liusir', "housir"]
#
# # res = [name+"_sb" for name in names]
# # print(res)
#
# res = map(lambda x: x + "_sb", names)
# # print(res)
# print(list(res))
​
# reduce
from functools import reduce
​
​
# res = reduce(lambda x, y: x + y, [1, 2, 3, 4, 5],100)
# res = reduce(lambda x, y: x + y, [1, 2, 3, 4, 5])
# res = reduce(lambda x, y: x + y, ["a",'b','c'])
# print(res)
​
​
# =============================================了解
# print(abs(-1))--------------->变成正数
# print(all([1, "aa", True]))-------->所有的布尔值都为True才是True,否则False
# print(any([0,"",True]))-------->布尔值有一个是True就是True
​
# print(all(""))  # True
# print(any([]))  # False
​
# print(bin(11))-------->换为二进制
# print(oct(11))-------->换为八进制
# print(hex(11))-------->换为十六进制
​
# print(callable(len))
# print(callable(10))----------->是否是内置函数
​
# aaaa = 1111111111
# def func():
#     x = 111111111
#     y = 2222222222222
#     print(globals())
#     print(locals())
#
# func()
​
# print(pow(10,2,3))  # 10 ** 2 % 3
​
​
# l = [1,2,3,4,5,6,7]
#
# s = slice(0,5,2)
# print(l[s])
#
#
# l1 = [11,222,333,444,555,666,777,88,999]
# print(l1[s])
​
# =============================================重点
# int
# float
# str
# list
# tuple
# dict
# set
# bool
# bytes
# s = frozenset({1,2,3})  # 不可变集合
# print(type(s))
​
​
​
# s = "print('hello')"
# s = "[1,2,3]"
# l = eval(s)
# print(l[0])
​
# with open('a.txt',mode='rt',encoding='utf-8') as f:
#     data = f.read()
#     # print(data,type(data))  # '{"name":"egon","age":18}'
#
#     dic = eval(data)
#     print(dic['name'])
​
​
​
​
# print("start...")
# i = 0
# while i < 3:
#     print(i)
#     i+=1
# print('end...')
#
# import base64
#
# exec(base64.b64decode('cHJpbnQoInN0YXJ0Li4uIikKaSA9IDAKd2hpbGUgaSA8IDM6CiAgICBwcmludChpKQogICAgaSs9MQpwcmludCgnZW5kLi4uJykK'))
#
​
​
​
​
# print(chr(65))
# print(ord("A"))  # 65
​
​
# l = [1,2,3]
# print(dir(l))
​
# print(divmod(100000,30))
​
# res = reversed([1,'a',3])
# print(list(res))
​
# l = [1,'a',3]
# # res1 = l[::-1]
# res1 = list(reversed(l))
# print(res1)
​
# print(round(3.6))
​
​
​
​
# x = "hello"
# y = [1,2,3]
# res = zip(x,y)
# # print(res)
# print(list(res))
​
​
# m=__import__("time")
​
# m.sleep(3)
​
​
​
​
# =============================================面向对象
# object
# classmethod
# staticmethod
# property
#
# hasattr
# getattr
# setattr
# delattr
​
# isinstance
# issubclass
​

 

三、面向过程编程

"""
面向过程编程
    核心是过程二字，过程指的是做事的步骤，即先干啥、再干啥、后干啥
​
    所以说，基于该思想编写程序就好比设计一条流水线
​
​
优点：
    复杂的问题流程化、进而简单化
​
缺点：
    扩展性差
​
​
"""

 

四、模块介绍

"""
1 什么是模块
    模块就是一系列功能的集合体，可以理解为"工具包"
​
    模块的四种类别：
        1、一个py文件就可以是一个模块，文件名m1.py,模块名为m1
        2、一个包含有__init__.py文件的文件夹称之为包，也是一种模块
        3、
        4、
​
    模块有三种来源：
        1、自带的
            内置
            标准库
​
        2、第三方模块：pip3 install requests
​
        3、自定义模块
​
2 为何要用模块
    拿来主义，提升开发效率
    解决冗余问题，让程序变得更加清晰
​
​
​
3 如何用模块
​
​
"""
import time
print(time)

 

五、区分py文件的两种用途

# 当文件被执行时，内置变量__name__的值为"__main__"
# 当文件被导入时，内置变量__name__的值为"模块名"
# print(__name__)
​
if __name__ == '__main__':
    # 测试功能
    f1()
    f2()