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rdataframerowfactorscolumnsorting

Going from a dataframe with a factor column and numeric column to a dataframe with factor levels as columns and corresponding numeric values as rows


If I take the following two-column dataframe, with one column being a factor and the other being a numeric vector:

data <- data.frame(x=c("a","b","c","d","e","f","g","h"), y = c(1,2,3,3,2,1,5,6))
data$x <- as.factor(data$x)

How can I turn it into a new dataframe data2 where the factor levels of data$x are columns and the rows contain the corresponding numeric values from data$y, like so?

structure(list(a = 1, b = 2, c = 3, d = 3, e = 2, f = 1, g = 5, 
    h = 6), class = "data.frame", row.names = c(NA, -1L))

Solution

  • With base R, use rbind.data.frame:

    d <- rbind.data.frame(data$y)
    colnames(d) <- data$x
    
      a b c d e f g h
    1 1 2 3 3 2 1 5 6
    

    With pivot_wider:

    tidyr::pivot_wider(data, names_from = x, values_from = y)
    
          a     b     c     d     e     f     g     h
    1     1     2     3     3     2     1     5     6
    

    or with xtabs:

    xtabs(y ~ ., data = data) |> 
        as.data.frame.list()
    
      a b c d e f g h
    1 1 2 3 3 2 1 5 6