map
m := make(map[string]int)
m["zhangsan"] = 22
m["lisi"] = 44
fmt.Println("map: ", m)
v1 := m["zhangsan"]
fmt.Println("v1: ", v1)
delete(m, "zhangsan")
fmt.Println("map: ", m)
clear(m)
fmt.Println("map: ", m)
_, prs := m["zhangsan"]
fmt.Println("prs: ",