根據列名稱在一個數據幀中查找值作爲另一個數據幀中的值存儲

Question

請參閱下面的可再現（剪切+粘貼）示例。實際數據集對11000人進行了4000多次串行觀測。我需要創建列A，B，C等，顯示與「疾病」變量的特定值的第一次出現相對應的「藥物」變量X，Y，Z等的NUMBER。這些數字是指對特定藥物採取的行動（開始，停止，增加劑量等）。「疾病」變量指的是疾病是否在包括耀斑和緩解的許多階段的疾病中發作。

例如：

Animal <- c("aardvark", "1", "cheetah", "dromedary", "eel", "1", "bison", "cheetah", "dromedary",  
"eel") 
Plant <- c("apple_tree", "blossom", "cactus", "1", "bronze", "apple_tree", "bronze", "cactus",  
"dragonplant", "1") 
Mineral <- c("amber", "bronze", "1", "bronze", "emerald", "1", "bronze", "bronze", "diamond",  
"emerald") 
Bacteria <- c("acinetobacter", "1", "1", "d-strep", "bronze", "acinetobacter", "bacillus", 
"chlamydia", "bronze", "enterobacter") 
AnimalDrugA <- c(1, 11, 12, 13, 14, 15, 16, 17, 18, 19) 
AnimalDrugB <- c(20, 1, 22, 23, 24, 25, 26, 27, 28, 29) 
PlantDrugA <- c(301, 302, 1, 304, 305, 306, 307, 308, 309, 310) 
PlantDrugB <- c(401, 402, 1, 404, 405, 406, 407, 408, 409, 410) 
MineralDrugA <- c(1, 2, 3, 4, 1, 6, 7, 8, 9, 10) 
MineralDrugB <- c(11, 12, 13, 1, 15, 16, 17, 18, 19, 20) 
BacteriaDrugA <- c(1, 2, 3, 4, 5, 6 , 7, 8, 9, 1) 
BacteriaDrugB <- c(10, 9, 8, 7, 6, 5, 4, 3, 2, 1) 
dummy_id <- c(1001, 2002, 3003, 4004, 5005, 6006, 7007, 8008, 9009, 10101) 


Elements <- data.frame(dummy_id, Animal, Plant, Mineral, Bacteria, AnimalDrugA, AnimalDrugB,   
PlantDrugA, PlantDrugB, MineralDrugA, MineralDrugB, BacteriaDrugA, BacteriaDrugB) 
ds <- Elements[,order(names(Elements))] 
ds #Got it in alphabetical order... The real data set will be re-ordered chronologically 


#Now I want the first occurrence of the word "bronze" for each id 
# for each subject 1 through 10. (That is, "bronze" corresponds to start of disease flare.) 
first.bronze <- colnames(ds)[apply(ds,1,match,x="bronze")] 
first.bronze 

#Now, I want to find the number in the DrugA, DrugB variable that corresponds to the first    
#occurrence of bronze. 
#Using the alphabetically ordered data set, the answer should be: 
#dummy_id DrugA DrugB 
#1...  NA NA 
#2...  2 12 
#3...  NA NA 
#4...  4  1 
#5...  5  6 
#6... NA NA 
#7... 7  17 
#8... 8  18 
#9... 9  2 
#10... NA NA 
#Note that all first occurrences of "bronze" 
# are in Mineral or Bacteria. 
#As a first step, join first.bronze to the ds 
ds$first.bronze <- first.bronze 
ds 

#Make a new ds where those who have an NA for first.bronze are excluded: 
ds2 <- ds[complete.cases(ds$first.bronze),] 
ds2 


# Create a template data frame 
out <- data.frame(matrix(nr = 1, nc = 3)) 
colnames(out) <- c("Form Number", "DrugA", "DrugB") # Gives correct column names 
out 

#Then grow the data frame...yes I realize potential slowness of computation 
test <- for(i in ds2$first.bronze){ 
    data <- rbind(colnames(ds2)[grep(i, names(ds2), ignore.case = FALSE, fixed = TRUE)]) 
    colnames(data) <- c("Form Number", "DrugA", "DrugB") # Gives correct column names 
    out <- rbind(out, data) 
} 
out 

#Then delete the first row of NAs 
out <- na.omit(out) 
out 

#Then add the appropriate dummy_ids 
dummy_id <- ds2$dummy_id 
out_with_ids <- as.data.frame(cbind(dummy_id, out)) 
out_with_ids 

現在我卡住了。我將ds2列的名稱列爲out_with_ids數據集中藥物A，藥物B的值。我已經徹底搜索了堆棧溢出，但基於匹配，合併，替換和data.table包的解決方案似乎不起作用。

謝謝！

Answer 1

我覺得這裏的問題是數據格式。我可以建議你把它存儲在「長」表中，像這樣：

library(data.table) 
dt <- data.table(dummy_id = rep(dummy_id, 4), 
       type = rep(c("Animal", "Bacteria", "Mineral", "Plant"), each = 10), 
       name = c(Animal, Bacteria, Mineral, Plant), 
       drugA = c(AnimalDrugA, BacteriaDrugA, MineralDrugA, PlantDrugA), 
       drugB = c(AnimalDrugB, BacteriaDrugB, MineralDrugB, PlantDrugB)) 

然後過濾和做其他操作要容易得多。例如，

dt[name == "bronze"][order(dummy_id)] 

坦率地說，我不知道我明白你最終想達到什麼目的。