如果第一列中的元素与另一个data.frame中的另一个元素匹配，如何替换数据帧第二列中的要素？

Question

I want to replace characters in second column of a data.frame if their first column matches in another data.frame. So the files are like this:

File1:

        Genotype          Group Type
1  08ZB02005DH01  08ZB02005DH01 Line
2  08ZB07005DH04  08ZB07005DH04 Line
3  08ZB08B06DH02  08ZB08B06DH02 Line
4  08ZB13005DH04  08ZB13005DH04 Line
5  08ZB18B24DH01  08ZB18B24DH01 Line
6 JRP4RA6121-002 JRP4RA6121-002 Line

File2:

       Genotype      POL       RE       ZE
1 08ZB08B06DH02 102.6110 94.94690 97.33455
2 08ZB18B24DH01 102.3411 94.18070 96.29505
3 08ZB02005DH01 101.0357 95.59205 96.62890
4 08ZB13005DH04 101.9972 96.57825 98.62155
5 08ZB07005DH04 103.5134 92.92665 96.10605

This is the code that I use:

Group_code1 <- 'TS'                     
Group_code2 <- 'PS'
for (i in 1:dim(file1)[1]) {
    if ((match(file1[i,1],file2[,1], nomatch=0)) >= 1) {test[i,2]<-Group_code2} else { test[i,2]<-Group_code2}

  }

what I expect as output is:

        Genotype Group Type
1  08ZB02005DH01  TS Line
2  08ZB07005DH04  TS Line
3  08ZB08B06DH02  TS Line
4  08ZB13005DH04  TS Line
5  08ZB18B24DH01  TS Line
6 JRP4RA6121-002  PS Line

but I get this error:

Warning messages:
1: In `[<-.factor`(`*tmp*`, iseq, value = "PS") :
  invalid factor level, NA generated

I would like to keep this part of the code(or at least something similar):

Group_code1 <- 'TS'                     
Group_code2 <- 'PS'

thanks in advance

Answer 1

如果df1是您的第一个data.frame而df2是第二个，则可以尝试：

df1$Group<-c("PS","TS")[ (df1$Group %in% df2$Genotype) +1]

Answer 2

An option using data.table

library(data.table) 
setkey(setDT(df1), Group)[df2[,1, drop=FALSE],
            Group:='TS'][Group!='TS', Group:='PS'][]
#         Genotype Group Type
#1:  08ZB02005DH01    TS Line
#2:  08ZB07005DH04    TS Line
#3:  08ZB08B06DH02    TS Line
#4:  08ZB13005DH04    TS Line
#5:  08ZB18B24DH01    TS Line
#6: JRP4RA6121-002    PS Line