A way to get Column Names as Row Names?

Question

My goal is to plot a map with each point representing the year of the highest measured value. So for that I need the year as one value and the Station Name as Row Name.

I get to the point where I get the year of the maximum value for each Station but don´t know how to get the station name as Row Name.

My example is the following:

set.seed(123)
df1<-data.frame(replicate(6,sample(0:200,2500,rep=TRUE)))
date_df1<-seq(as.Date("1995-01-01"), by = "day", length.out = 2500)
test_sto<-cbind(date_df1, df1)
test_sto$date_df1<-as.Date(test_sto$date_df1)
test_sto<-test_sto%>%    dplyr::mutate(     year = lubridate::year(date_df1), 
                                    month = lubridate::month(date_df1),
                                    day = lubridate::day(date_df1))

This is my Dataframe, i then applied the following steps:

To get all values above the treshold for each year and station:

test_year<-aggregate.data.frame(x=test_sto[2:7] > 120, by = list(test_sto$year), FUN = sum, na.rm=TRUE )

This works as it should, the nex is the following

m <- ncol(test_year)
Value <- rep(NA,m)

for (j in 2:m) {
  idx<- which.max(test_year[,j])
    Value[j] <- test_year[,1][idx]
}
  
test_test<-Value[2:m]

At the end of this, I get the following table:

	x
1	1996
2	1996
3	1998
4	1996
5	1999
6	1999

But instead of the 1,2,3,4,5..I need there my Column Names (X1,X2,X3 etc.):

	x
X1	1996
X2	1996
X3	1998
X4	1996
X5	1999
X6	1999

but this is the point where i´m struggeling. I tried it with the following step:

test_year$max<-apply(test_year[2:7], 1, FUN = max)
apply(test_year[2:7], 2, FUN = max)
test_year2<-subset(test_year, ncol(2:7) == max(ncol(2:7)))

But i´m just getting an error message saying:

in max(ncol(2:7)): non not-missing Argument for max; give -Inf back<

Maybe someone knows a work around! Thanks in advance!

Answer 1

The 'test_test' is just a vector. Its magnitude characterized by length and is a one 1 dimensional object which doesn't have row.names attribute. But, we can have names attribute

names(test_test) <- colnames(test_year)[-1]