python整理集合学习

1 python_name &＃61; {"alex","tom","jime","limei"}
2 linux_name &＃61; {"alex","tom","zhangsan"}
3 p_n &＃61; set(python_name)
4 l_n &＃61; set(linux_name)
5 #求交集
6 print(p_n.intersection(l_n))
7 print(p_n & l_n)
8 #求并集
9 print(p_n.union(l_n))
10 print(p_n | l_n)
11 #求差集
12 print(p_n.difference(l_n))
13 print(p_n-l_n)
14 #交叉补集
15 print(p_n.symmetric_difference(l_n))
16 print(p_n^l_n)

1 #字符串格式化
2 t &＃61; "i am %s " % "tom"
3 print(t)
4 #%s可以是任意值&＃xff08;字符串、数字&＃xff0c;列表&＃xff0c;元祖&＃xff0c;字典&＃xff09; %d只可以接收数字
5 t &＃61; "i am %s age %d " % ("tom",18)
6 print(t)
7 #浮点数&＃xff08;小数&＃xff09;%f 默认保留六位小数 %.2f保留2位小数 %.3s字符串截取操作
8 t &＃61; &＃39;percent %.2f &＃39; % 99.942562
9 print(t)
10 #打印百分比%%
11 t &＃61; &＃39;percent %.2f %%&＃39; % 99.942562
12 print(t)
13 #%(name)s %(age)d 键值 对应的传字典key对应的值
14 t &＃61; "i am %(name)s age %(age)d " % {"name":"alex","age":18}
15 print(t)

1 python中函数定义方法&＃xff1a;
2
3 def test(x):
4 "The function definitions"
5 x&＃43;&＃61;1
6 return x
7
8 def:定义函数的关键字
9 test&＃xff1a;函数名
10 &＃xff08;&＃xff09;&＃xff1a;内可定义形参
11 "":文档描述&＃xff08;非必要&＃xff0c;但是强烈建议为你的函数添加描述信息&＃xff09;
12 x&＃43;&＃61;1&＃xff1a;泛指代码块或程序处理逻辑
13 return&＃xff1a;定义返回值

1 #定义全局变量
2 name &＃61; "tom"
3 age &＃61;18
4 def chang_name():
5 global name,age #指定局部变量为全局变量
6 age &＃61; 11
7 name&＃61; "alex" #局部变量
8 print("chang_name",name,age)
9 chang_name() #变量参数
10 print(name,age)

#/函数之前的嵌套
NAME &＃61; "ALEX"
def tom():name &＃61; "zhangsan"print(name)def arm(): #嵌套函数name &＃61; "zhaosi"print(name)def li(): #嵌套函数name &＃61; "wangwu"print(name)print(name)li()arm()print(name)
tom()
print(NAME)

1 name &＃61; "alex"
2 def zhangsan():
3 name &＃61; "zhangsan"
4 def lisi():
5 # global name #全局变量
6 nonlocal name #上一级局部变量
7 name &＃61; "lisi"
8 return
9 lisi()
10 print(name)
11 print(name)
12 zhangsan()
13 print(name)