CODEWITHSUNDEEP
rdplyr
Seydou GORO
Seydou GORO

Reputation: 1285

How to find the statistical mode of each ID

Here are the observations of two individuals of my dataset.

data=structure(list(id = c(2L, 2L, 2L, 3L, 3L, 3L), trt = c(1L, 1L, 
1L, 1L, 1L, 1L), status = c(0L, 0L, 0L, 2L, 2L, 2L), stage = c(3L, 
3L, 3L, 4L, 4L, 4L), spiders = c(1L, 1L, 1L, 0L, 1L, 0L), sex = structure(c(2L, 
2L, 2L, 1L, 1L, 1L), .Label = c("m", "f"), class = "factor"), 
    hepato = c(1L, 1L, 1L, 0L, 1L, 0L), edema = c(0, 0, 0, 0.5, 
    0, 0.5), ascites = c(0L, 0L, 0L, 0L, 0L, 0L)), row.names = c(NA, 
-6L), class = "data.frame")

I want to calculate the the statistical mode for each individual after grouping by id. I used this code below:

library(dplyr)
library(modeest)

    data%>%
      group_by(id)%>%mutate(edema2=mlv(edema))

And I get an error message when calculating the mode, while this method work well with other statistical parameters such as mean, sd, min, max....

Upvotes: 0

Views: 154

Answers (1)

Ronak Shah
Ronak Shah

Reputation: 388797

The warnings that you are getting are suggesting two things.

  1. You have not specified what method to choose so default method 'shorth' is used.

  2. It is suggesting that there is a tie in selection of Mode value.

Alternatively, why not use the Mode function from here :

Mode <- function(x) {
  ux <- unique(x)
  ux[which.max(tabulate(match(x, ux)))]
}

To apply by group you can use it with dplyr as :

library(dplyr)
data%>% group_by(id)%>% mutate(edema2= Mode(edema))

#     id   trt status stage spiders sex   hepato edema ascites edema2
#  <int> <int>  <int> <int>   <int> <fct>  <int> <dbl>   <int>  <dbl>
#1     2     1      0     3       1 f          1   0         0    0  
#2     2     1      0     3       1 f          1   0         0    0  
#3     2     1      0     3       1 f          1   0         0    0  
#4     3     1      2     4       0 m          0   0.5       0    0.5
#5     3     1      2     4       1 m          1   0         0    0.5
#6     3     1      2     4       0 m          0   0.5       0    0.5

Upvotes: 4

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