您可以使用sapply：

df$test <- sapply(1:nrow(df), 
                  function(x) df[x, names(df) == df[x,1]])

输出：

#   target   col1  col2     col3     test
# 1   col1  green   one      dog    green
# 2   col1   pink   two      cat     pink
# 3   col3   blue three   spider   spider
# 4   col2  black  four      pig     four
# 5   col3 purple  five elephant elephant
# 6   col2 yellow   six     lion      six

注我创建了一个test列来检查，但您可以直接覆盖target
数据类型

df <- read.table(text = "target  col1         col2      col3 
col1    green        one       dog
col1    pink         two       cat
col3    blue         three     spider  
col2    black        four      pig
col3    purple       five      elephant
col2    yellow       six       lion", header = TRUE)

基本矢量化方法：如果使用带“[”的两列数值矩阵，则可以获取行和列的值。

dat <- read.table(text="target  col1         col2      col3 
col1    green        one       dog
col1    pink         two       cat
col3    blue         three     spider  
col2    black        four      pig
col3    purple       five      elephant
col2    yellow       six       lion", head=TRUE)
# extract col number from first column and add one to offset it
# then use that as the column numer for 
dat[ matrix( c( 1:nrow(dat), as.numeric(gsub("col", "", dat[[1]]))+1 ), ncol=2) ]
 [1] "green"    "pink"     "spider"   "four"     "elephant" "six"

然后将其分配到“目标”列。

>  dat[, 1] <- dat[ matrix( c( 1:nrow(dat), as.numeric(gsub("col", "", dat[[1]]))+1 ), ncol=2) ]
> dat
    target   col1  col2     col3
1    green  green   one      dog
2     pink   pink   two      cat
3   spider   blue three   spider
4     four  black  four      pig
5 elephant purple  five elephant
6      six yellow   six     lion