Conditionally change value and finding combinations-CodePudding

I have a vector (testCol_1) consisting of 3 letters. Each letter is binary and can be replaced by either 0 or 1.

THE RULE is, if one letter (e.g. S) is replaced by a number (e.g. 1), all the S in the vector will also be replaced by that same number.

I would like to find all the possible combinations; for the following reproducible example, there are 8 possible combinations.

test <- expand.grid(rep(list(c("S","E","F")),4))
testCol_1 <- test$Var1

My solution:

This is my own solution but as you can see this is rather novice and I am quite sure there are better way to solve this.

# Changing to integer
testCol_1 <- as.integer(testCol_1)
# Finding all the combinations first
temp.combo <- expand.grid(rep(list(0:1),3))
test.final.result <- list()
for (i in 1:nrow(temp.combo)){
  testSol <- replace(testCol_1, testCol_1 == 1,temp.combo[i,1])
  testSol <- replace(testSol, testSol == 2,temp.combo[i,2])
  testSol <- replace(testSol, testSol == 3,temp.combo[i,3])
  test.final.result[[i]] <- testSol
}

CodePudding user response：

Here is a solution with no loops, use R's vectorized instructions to get the 0/1 directly from temp.combo, by subsetting it, run the following to see it:

temp.combo[, testCol_1]

Note also that nvals is not strictly needed, it only makes the code more readable.

test <- expand.grid(rep(list(c("S","E","F")), 4))
testCol_1 <- as.integer(test$Var1)
nvals <- length(unique(testCol_1))

temp.combo <- expand.grid(rep(list(0:1), nvals))

temp <- as.data.frame(t(temp.combo[, testCol_1]))
test.final.result <- as.list(temp)
test.final.result
#> $V1
#>  [1] 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
#> [39] 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
#> [77] 0 0 0 0 0
#> 
#> $V2
#>  [1] 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0
#> [39] 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1
#> [77] 0 0 1 0 0
#> 
#> $V3
#>  [1] 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1
#> [39] 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0
#> [77] 1 0 0 1 0
#> 
#> $V4
#>  [1] 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1
#> [39] 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1
#> [77] 1 0 1 1 0
#> 
#> $V5
#>  [1] 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0
#> [39] 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0 0 1 0
#> [77] 0 1 0 0 1
#> 
#> $V6
#>  [1] 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0
#> [39] 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1
#> [77] 0 1 1 0 1
#> 
#> $V7
#>  [1] 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1
#> [39] 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0
#> [77] 1 1 0 1 1
#> 
#> $V8
#>  [1] 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
#> [39] 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
#> [77] 1 1 1 1 1

^{Created on 2022-09-30 with reprex v2.0.2}