Question

您好，我想知道最简单的命令（不使用诸如deplyr的任何其他库）如何找到R的下面数据帧，如何找到第二高的薪水并将雇员的姓名存储在名为2nd_high_employee的变量中？

EmployeeID  EmployeeName    Department      Salary   
----------- --------------- --------------- ---------
1           T Cook          Finance         40000.00
2           D Michael       Finance         25000.00
3           A Smith         Finance         25000.00
4           D Adams         Finance         15000.00
5           M Williams      IT              80000.00
6           D Jones         IT              40000.00
7           J Miller        IT              50000.00
8           L Lewis         IT              50000.00
9           A Anderson      Back-Office     25000.00
10          S Martin        Back-Office     15000.00
11          J Garcia        Back-Office     15000.00
12          T Clerk         Back-Office     10000.00

Answer 1

下次，您可以考虑使用head（dput（x））发布数据样本，以使SO成员轻松读取数据。

df <- read.table(text = "
EmployeeID  EmployeeName    Department      Salary   

1           T Cook          Finance         40000.00
2           D Michael       Finance         25000.00
3           A Smith         Finance         25000.00
4           D Adams         Finance         15000.00
5           M Williams      IT              80000.00
6           D Jones         IT              40000.00
7           J Miller        IT              50000.00
8           L Lewis         IT              50000.00
9           A Anderson      Back-Office     25000.00
10          S Martin        Back-Office     15000.00
11          J Garcia        Back-Office     15000.00
12          T Clerk         Back-Office     10000.00", header = T)


second_high_employee <- tail(sort(df$Salary),2)[1]
second_high_employee 
[1] 50000

顺便说一句，不可能用数字开头对象名称。您可以检查：?make.names

此外，对于每个部门，您都可以这样做：

aggregate(Salary ~ Department, df, function(x) {tail(sort(x), 2)[1]})
   Department Salary
1 Back-Office  15000
2     Finance  25000
3          IT  50000

如果有2个最高薪水是80000，而您又想找到第二个最高薪水50000，则可以将x或df$Salaray包装在tail(sort(unique()), 2)[1]

Answer 2

使用基数R：找到第二高的工资：

如果您需要子集而不考虑部门：

subset(dat,sort(z<-rank(Salary),T)[2]==z)
  EmployeeID EmployeeName Department Salary
7          J       Miller         IT  50000
8          L        Lewis         IT  50000

如果考虑部门，则：

unsplit(by(dat,dat$Department,function(x)subset(x,(y<-rank(Salary))==sort(y,T)[2])),rep(1:3,each=2))   

   EmployeeID EmployeeName  Department Salary
10          S       Martin Back-Office  15000
11          J       Garcia Back-Office  15000
2           D      Michael     Finance  25000
3           A        Smith     Finance  25000
7           J       Miller          IT  50000
8           L        Lewis          IT  50000

只需输入员工姓名：

as.character(subset(dat,sort(z<-rank(Salary),T)[2]==z)[,2])
[1] "Miller" "Lewis"

在R中的数据框中找到第二个最大值

2 个答案: