Find the second highest value in data frame in R - r

Question

Hello for below data frame in R, may I know the simplest command (without using any additional library like deplyr) how to find the second highest salary and store the name of the employee in a variable named 2nd_high_employee?
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

Next time you could consider to post a sample of your data using head(dput(x)), to ease SO members to read in your data.
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$Salary),2)[1]
second_high_employee
[1] 50000
BTW, it is not possible to start an object name with a number. You could check: ?make.names
Also, for for each department you could do:
aggregate(Salary ~ Department, df, function(x) {tail(sort(x), 2)[1]})
Department Salary
1 Back-Office 15000
2 Finance 25000
3 IT 50000
In case there had been 2 top salaries of 80000 and you had wanted to find the second highest of 50000 again, you could have wrapped x or df$Salaray inside tail(sort(unique()), 2)[1]

Answer 2

Using Base R: Finding the 2nd highest salary:
if you need the subset without taking into consideration the department:
subset(dat,sort(z<-rank(Salary),T)[2]==z)
EmployeeID EmployeeName Department Salary
7 J Miller IT 50000
8 L Lewis IT 50000
if taking into consideration the department:
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
Just for the employee name:
as.character(subset(dat,sort(z<-rank(Salary),T)[2]==z)[,2])
[1] "Miller" "Lewis"