R data.table替换多列中的值

我对R和stackoverflow都是新手。我试图找出data.table，然后看着“R data.table替换另一个data.table中的值索引”，我想我理解了，但无法得到我想要的

我有两个数据帧-第一个是我感兴趣的数据，第二个是包含名称/ID的键，用于转换第一个数据帧中的ID。我想使用“key”data.table将表$id1和表$id2中的数字转换为“key”data.table中的“name”。以下是我迄今为止所做的工作：

table<-data.table("Sample" = sample(40:46, 6), "Conc1" = sample(100:106,6), 
              "id1" = as.character(sample(1:6, 6)), "Conc2" = sample(200:206,6),
              "id2" = as.character(sample(1:6, 6))) 

key<-data.table("Name" = c("Sally", "John", "Roger", "Bob", "Kelsey", "Molly"), 
            "id1" = as.character(1:6))

setkey(table, id1)
setkey(key, id1)

table[key, `:=`(id1 = i.Name)]

---

表执行此操作的另一种方法：

dt <- merge(table,key,by.x = c('id1'),by.y = c('id1'),sort=F)

table <- merge(dt,key,by.x = c('id2'),by.y = c('id1'),sort=F)

table[,id1 := Name.x]
table[,id2 := Name.y]
table[,Name.x := NULL]
table[,Name.y := NULL]

##      id2    id1 Sample Conc1 Conc2
##1:    Bob    Bob     41   101   200
##2: Kelsey   John     46   100   203
##3:  Roger  Molly     43   102   206
##4:  Sally Kelsey     42   105   201
##5:   John  Roger     44   106   202
##6:  Molly  Sally     45   104   204

dt在
data.table
中，无需设置键即可进行连接。您可以在
on=
参数中指定联接列

library(data.table) ## v1.9.6 +

## update id1 based on Name
table[ key, on = c("id1"), nomatch = 0, id1 := i.Name]
## here the id1 column is getting updated to i.Name 
## (the 'i.' is the prefix given to columns on the 'right' side of the join).

## update id2 based on Name
table[ key, on = c(id2 = "id1"), nomatch = 0, id2 := i.Name]

table

#   Sample Conc1    id1 Conc2    id2
#1:     40   100   John   201   John
#2:     43   101 Kelsey   206 Kelsey
#3:     45   103  Molly   205  Roger
#4:     42   102  Roger   204    Bob
#5:     44   104  Sally   200  Molly
#6:     41   105    Bob   202  Sally

从
data.table v1.9.6开始
可以使用
on=
参数在不同的列名上进行连接

library(data.table) ## v1.9.6 +

## update id1 based on Name
table[ key, on = c("id1"), nomatch = 0, id1 := i.Name]
## here the id1 column is getting updated to i.Name 
## (the 'i.' is the prefix given to columns on the 'right' side of the join).

## update id2 based on Name
table[ key, on = c(id2 = "id1"), nomatch = 0, id2 := i.Name]

table

#   Sample Conc1    id1 Conc2    id2
#1:     40   100   John   201   John
#2:     43   101 Kelsey   206 Kelsey
#3:     45   103  Molly   205  Roger
#4:     42   102  Roger   204    Bob
#5:     44   104  Sally   200  Molly
#6:     41   105    Bob   202  Sally


数据

## setting seed because we are sampling
set.seed(1234)
table<-data.table("Sample" = sample(40:46, 6), "Conc1" = sample(100:106,6), 
                  "id1" = as.character(sample(1:6, 6)), "Conc2" = sample(200:206,6),
                  "id2" = as.character(sample(1:6, 6))) 

key<-data.table("Name" = c("Sally", "John", "Roger", "Bob", "Kelsey", "Molly"), 
                "id1" = as.character(1:6))

###正在播种，因为我们正在采样
种子集（1234）
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