[R] categorizing data

Richard O'Keefe r@oknz @end|ng |rom gm@||@com
Mon May 30 07:07:25 CEST 2022


Suppose your data are in a table called plant.data
Suppose you want to process row i.
Then plant.data[i,] is a vector of 3 numbers.
ord <- order(plant.data[i,])
gives you a vector of 3 positive integers such
that plant.data[i,ord] is in ascending order.
plant.data[i,ord[1]] <- 10
plant.data[i,ord[2]] <- 30
plant.data[i,ord[3]] <- 50
or even
plant.data[i,ord] <- c(10,30,50)
Wrapping it up and tying a bow on it:
new.values <- c(10,30,50)
for (i in 1:nrow(plant.data))
    plant.data[i,order(plant.data[i,])] <- new.values

> plant.orig <- data.frame(
+ tree = c(32,23,49),
+ shrub = c(11,41,23),
+ grass = c(47,26,18))
> plant.orig
  tree shrub grass
1   32    11    47
2   23    41    26
3   49    23    18
> new.values <- c(10,30,50)
> plant.new <- plant.orig
> for (i in 1:nrow(plant.new))
+     plant.new[i,order(plant.new[i,])] <- new.values
> plant.new
  tree shrub grass
1   30    10    50
2   10    50    30
3   50    30    10


On Mon, 30 May 2022 at 07:29, Janet Choate <jsc.eco using gmail.com> wrote:

> Hi R community,
> I have a data frame with three variables, where each row adds up to 90.
> I want to assign a category of low, medium, or high to the values in each
> row - where the lowest value per row will be set to 10, the medium value
> set to 30, and the high value set to 50 - so each row still adds up to 90.
>
> For example:
> Data: Orig
> tree  shrub  grass
> 32     11       47
> 23      41      26
> 49      23      18
>
> Data: New
> tree  shrub  grass
> 30      10      50
> 10       50     30
> 50       30     10
>
> I am not attaching any code here as I have not been able to write anything
> effective! appreciate help with this!
> thank you,
> JC
>
> --
>
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