Select number of alternatives depending on chosen method-CodePudding

The code below checks the correlation of three methods (TOPSIS, PROMETHEE and VIKOR) with a specific method (DISTANCE), and the one with the highest correlation is chosen. In this case below, it is TOPSIS.

library(dplyr)
library(tidyr)

df<-structure(list(Alternatives = c(3, 4, 5, 6, 7, 8, 9, 10, 11, 12), 
    DISTANCE = c(1L, 10L, 7L, 8L, 9L, 6L, 5L, 3L, 4L, 2L),  TOPSIS = c(1L, 
    8L, 7L, 6L, 10L, 9L, 4L, 3L, 2L, 5L),  PROMETHEE = c(1L, 10L, 
    7L, 8L, 9L, 6L, 4L, 2L, 3L, 5L),  VIKOR = c(1, 9, 7, 6, 10, 
    8, 5, 4, 3, 2)), class = "data.frame", row.names = c(NA, 
-10L))

> df
   Alternatives DISTANCE TOPSIS PROMETHEE VIKOR
1             3        1      1         1     1
2             4       10      8        10     9
3             5        7      7         7     7
4             6        8      6         8     6
5             7        9     10         9    10
6             8        6      9         6     8
7             9        5      4         4     5
8            10        3      3         2     4
9            11        4      2         3     3
10           12        2      5         5     2


output<-df %>% 
   summarise(across(TOPSIS:VIKOR,   ~cor.test(., DISTANCE, 
       method = "spearman")$estimate)) %>%
  pivot_longer(cols = everything()) %>%
  slice_head(n=1) %>%
  slice_max(value) %>%
  pull(name) %>%
  select(df, .)


   TOPSIS
1       1
2       8
3       7
4       6
5      10
6       9
7       4
8       3
9       2
10      5

Now, I'd like to consider my column Alternatives from my df dataframe along with the result of output, and generate a variable k, which is the number of alternatives when the method value is 1. Example:

   Alternatives   TOPSIS
1        3          1
2        4          8
3        5          7
4        6          6
5        7         10
6        8          9
7        9          4
8        10         3
9        11         2
10       12         5

So the value of k would be equal to 3, because 1 is in the row of Alternatives = 3.

CodePudding user response：

You can use the following code:

output<-df %>% 
  summarise(across(TOPSIS:VIKOR,   
                   ~cor.test(., DISTANCE,method = "spearman")$estimate)) %>%
  pivot_longer(cols = everything()) %>%
  slice_head(n=1) %>%
  slice_max(value) %>%
  pull(name) %>% 
  all_of(.) %>%
  select(df, Alternatives, . ) %>%
  filter (.[[2]] == 1)

The above code will return a tibble:

##  Alternatives TOPSIS
##1            3      1

You can extract then extract the value from the column Alternatives if needed.