CODEWITHSUNDEEP
rdataframe
James Prentice
James Prentice

Reputation: 55

R order columns in a two-way table based on Row values

I am trying to order the columns within a two-way table I have created based upon row values. I have saved the two-way table as a table, thus putting it into a dataframe (I am using R). The below code should create a two-way table based on the built-in Iris data.

In the example I have given, see the attached picture, if you ordered the columns based upon the first row the column order should be setosa, virginica, Versicolor. The second row would order the columns virginica, Versicolor, Setosa. The third row would order the columns as Versicolor, virginica, setosa. so far the only solution I have is WinEUref19[,order(WinEUref19[nrow(WinEUref19),])] but this can only do the last row, is it possible to order the columns by the second or first row?

Replciable code:

Data <- iris
Data $ var2 <- iris $ Species
Data $ var2 <- sample(Data $ var2)
Df <-table(Data $ var2, iris $ Species)
rownames(Df) <- c("Row one","Row two", "Row three")
Df

            setosa versicolor virginica
  Row one       14         19        17
  Row two       22         15        13
  Row three     14         16        20

Upvotes: 1

Views: 724

Answers (2)

Martin Wettstein
Martin Wettstein

Reputation: 2904

Yes, you can order by any row. Just compute the order of the values and set the resulting vector as a selection criterion for the columns.

> Df[,order(Df[1,])]
           
            setosa versicolor virginica
  Row one       15         17        18
  Row two       18         15        17
  Row three     17         18        15

> Df[,order(Df[2,])]
           
            versicolor virginica setosa
  Row one           17        18     15
  Row two           15        17     18
  Row three         18        15     17

> Df[,order(Df[3,])]
           
            virginica setosa versicolor
  Row one          18     15         17
  Row two          17     18         15
  Row three        15     17         18

Upvotes: 0

MGP
MGP

Reputation: 2551

You basically have the answer already. you can order the table by the first row like this:

Df[,order(Df[1,])]

By the second row like this:

Df[,order(Df[2,])]

and so on.

Upvotes: 0

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