Save the wrong name with indexing

Question

I need to specify data.frame columns with duplicate names. inside data.frame you can use check.names = FALSE to do the mischievous act of the name. But if you specify this, you lose naughty names when indexing. I want to keep these names. So beloe is an example and the result that I get, and I would like to get:

 x <- data.frame(b= 4:6, a =6:8, a =6:8, check.names = FALSE) x[, -1] 

I get:

  a a.1 1 6 6 2 7 7 3 8 8 

I would like to:

  aa 1 6 6 2 7 7 3 8 8 

Answer 1

How about this:

 subdf <- function(df, ii) { do.call("data.frame", c(as.list(df)[ii], check.names=FALSE)) } subdf(x, -1) # aa # 1 6 6 # 2 7 7 # 3 8 8 subdf(x, 2:3) # aa # 1 6 6 # 2 7 7 # 3 8 8 

Answer 2

Here's an ugly solution

 > tmp <- data.frame(b=4:6, a=6:8, a=6:8, check.names=FALSE) > setNames(tmp[, -1], names(tmp)[-1]) aa 1 6 6 2 7 7 3 8 8 

Answer 3

Looking at the code for [.data.frame , it gives this as part of the code

 if (anyDuplicated(cols)) names(y) <- make.unique(cols) 

and I could not see anything in the code that would allow me to skip this check. Looks like we just need to write our own function. It is not very safe, although I'm sure a much better version can be created ...

 dropCols <- function(x, cols){ nm <- colnames(x) x <- x[, -cols] colnames(x) <- nm[-cols] x } x <- data.frame(b= 4:6, a =6:8, a =6:8, check.names = FALSE) #x[, -1] dropCols(x, 1) # aa #1 6 6 #2 7 7 #3 8 8 

Answer 4

per dirks tongue in the cheek comment:

 safe.data.frame <- function(dat, index) { colnam <-colnames(dat)[index] dat2 <- dat[, index] colnames(dat2) <- colnam dat2 } safe.data.frame(x, -1) 

I was hoping for something better :)