在r中相交比较向量

Question

I have a dataframe with 4 colums here is the structure.

I would like to create a new vector (valuetofind) with the value of 1 if all my rows have the number 1 and -1 if all my rows have the number -1.
Otherwhise just fill with NA.

str(results)
'data.frame':   435 obs. of  4 variables:
 $ model.knn: Factor w/ 2 levels "-1","1": 2 2 2 2 2 2 2 1 2 2 ...
 $ p.arbre  : Factor w/ 2 levels "-1","1": 2 2 1 1 2 2 2 1 2 2 ...
 $ p.svm    : Factor w/ 2 levels "-1","1": 2 2 2 2 2 2 2 2 2 2 ...
 $ p.rf     : Factor w/ 2 levels "-1","1": 2 2 2 1 2 2 2 1 2 2 ...


model.knn p.arbre p.svm p.rf  Valuetofind
    1        1      1    1         1
   -1       -1      1    1        NA
   -1       -1     -1   -1        -1

I have been trying many things but I am blocked

I tried to convert to numeric, the facor in my dataframe. It gave me values of 2 and 1 instread of my -1 and 1.

Answer 1

Use nested ifelse() and rowSums() for base solution.

results <- data.frame(model.knn = c(1, -1, -1), p.arbre = c(1, -1, -1), p.svm = c(1, 1, -1), p.rf = c(1, 1, -1))

results["Valuetofind"] <- ifelse(rowSums(results) == ncol(results), 1, 
                                  ifelse(rowSums(results) == -ncol(results), -1, NA))

results
  model.knn p.arbre p.svm p.rf Valuetofind
1         1       1     1    1           1
2        -1      -1     1    1          NA
3        -1      -1    -1   -1          -1

You can try dplyr::case_when() if there are multiple ifelse() nesting.