[R] Trying to fix code that will find highest 5 column names and their associated values for each row in a data frame in R

[David L Carlson]

There are some problems with your example. Your code does not produce anything like your example data frame because you draw only 9 values without replacement. Your code produces 10 columns, each with the same permutation of the values 1:9.

Then your desired output does not make sense in terms of your example data. The first entry is V2:9 but 9 does not appear in row 1.

Using your posted example:
DF <- structure(list(V1 = c(3L, 1L, 2L, 3L, 6L, 8L, 1L, 9L, 1L),
V2 = c(2L, 4L, 3L, 8L, 2L, 2L, 5L, 3L, 2L), V3 = c(5L, 7L, 4L, 3L,
3L, 4L, 3L, 5L, 4L), V4 = c(6L, 8L, 7L, 4L, 7L, 8L, 6L, 8L, 8L),
V5 = c(5L, 7L, 5L, 5L, 2L, 3L, 8L, 4L, 3L), V6 = c(2L, 7L, 8L, 6L,
1L, 2L, 3L, 9L, 2L), V7 = c(6L, 3L, 9L, 7L, 8L, 9L, 8L, 7L, 1L),
V8 = c(8L, 4L, 1L, 4L, 3L, 7L, 9L, 8L, 2L), V9 = c(1L, 2L, 3L, 6L,
2L, 6L, 1L, 1L, 5L), V10 = c(3L, 9L, 5L, 5L, 4L, 5L, 3L, 2L, 6L)), 
class = "data.frame", row.names = c(NA, -9L))

Your code produces:

     V1    V2   V3    V4    V5
1  V8:8  V4:6 V7:6  V3:5  V5:5
2 V10:9  V4:8 V3:7  V5:7  V6:7
3  V7:9  V6:8 V4:7  V5:5 V10:5
4  V2:8  V7:7 V6:6  V9:6  V5:5
5  V7:8  V4:7 V1:6 V10:4  V3:3
6  V7:9  V1:8 V4:8  V8:7  V9:6
7  V8:9  V5:8 V7:8  V4:6  V2:5
8  V1:9  V6:9 V4:8  V8:8  V7:7
9  V4:8 V10:6 V9:5  V3:4  V5:3

Which seems to be what you wanted.

---------------------------------------------
David L. Carlson
Department of Anthropology
Texas A&M University


-----Original Message-----
From: R-help [mailto:r-help-bounces using r-project.org] On Behalf Of Tom Woolman
Sent: Monday, December 17, 2018 11:34 AM
To: r-help using r-project.org
Subject: [R] Trying to fix code that will find highest 5 column names and their associated values for each row in a data frame in R


I have a data frame each with 10 variables of integer data for various
  attributes about each row of data, and I need to know the highest 5  
variables related to each of
  row in this data frame and output that to a new data frame. In addition to
  the 5 highest variable names, I also need to know the corresponding 5
  highest variable values for each row.

  A simple code example to generate a sample data frame for this is:

  set.seed(1)
  DF <- matrix(sample(1:9,9),ncol=10,nrow=9)
  DF <- as.data.frame.matrix(DF)


This would result in an example data frame like this:

  #   V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
  # 1  3  2  5  6  5  2  6  8  1   3
  # 2  1  4  7  8  7  7  3  4  2   9
  # 3  2  3  4  7  5  8  9  1  3   5
  # 4  3  8  3  4  5  6  7  4  6   5
  # 5  6  2  3  7  2  1  8  3  2   4
  # 6  8  2  4  8  3  2  9  7  6   5
  # 7  1  5  3  6  8  3  8  9  1   3
  # 8  9  3  5  8  4  9  7  8  1   2
  # 9  1  2  4  8  3  2  1  2  5   6


  My ideal output would be something like this:


  #      V1   V2   V3   V4   V5
  # 1  V2:9 V7:8 V8:7 V4:6 V3:5
  # 2  V9:9 V3:8 V5:7 V7:6 V4:5
  # 3  V5:9 V3:8 V2:7 V9:6 V7:5
  # 4  V8:9 V4:8 V2:7 V5:6 V9:5
  # 5  V9:9 V1:8 V6:7 V3:6 V5:5
  # 6  V8:9 V1:8 V5:7 V9:6 V4:5
  # 7  V2:9 V8:8 V7:7 V5:6 V9:5
  # 8  V4:9 V7:8 V9:7 V2:6 V8:5
  # 9  V3:9 V7:8 V8:7 V4:6 V5:5
  # 10 V6:9 V8:8 V1:7 V9:6 V4:5


  I was trying to use code, but this doesn't seem to work:

  out <- t(apply(DF, 1, function(x){
    o <- head(order(-x), 5)
    paste0(names(x[o]), ':', x[o])
  }))
  as.data.frame(out)



  Thanks everyone!

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