Search code examples
rreshape2

I want to turn column names into an identifying column in R

Hey guys I'm pretty new to R so apologies if this is a dumb question. I have a data frame that looks like this:

Gelatin Geltrex Combo Control
1   0.761   0.732 0.557   0.723
2   0.704   0.712 0.764   0.540
3   0.580   0.435 0.351   0.537

I want to end up with 2 columns; one with the numbers in the row and another column with the current column names as identifiers for the numbers?

Solution

  • If we need row/column index we can use row and col to get the row/column index and create a new dataset with data.frame. 

    df2 <- data.frame(Row= c(row(df1)), 
               Col=names(df1)[col(df1)], stringsAsFactors=FALSE)

    Or another option is melt from library(reshape2). We convert the 'data.frame' to 'matrix' and melt to get the row/column names as the first two columns.

    library(reshape2)
melt(as.matrix(df1))[-3]

    EDIT: If we need the value and column names as the two columns, just melt or use stack as @thelatemail mentioned

    melt(df1)

    Or stack from base R

    stack(df1)