r - 仅将嵌套数据帧的一列除以整数值

Question

我希望将数据框的第三列除以 5。这些数据框是嵌套的，如下所示:

[[44]]
    Ethnicity      Variant  Sum
 1:       ASW     ACCEPTOR    1
 2:       ASW          CDS   68
 3:       ASW   CGA_CNVWIN 1000
 4:       ASW     CGA_MIRB    0
 5:       ASW       DELETE    0
 6:       ASW      DISRUPT    0
 7:       ASW        DONOR    0
 8:       ASW   FRAMESHIFT    0
 9:       ASW       INSERT    1
10:       ASW       INTRON   54

我使用了三个命令，每个命令都成功但有脱靶效果。

lapply(ASWldtSUM,function(x)(x/5))

返回

[[44]]
    Ethnicity Variant   Sum
 1:        NA      NA   0.2
 2:        NA      NA  13.6
 3:        NA      NA 200.0
 4:        NA      NA   0.0
 5:        NA      NA   0.0

它具有将所有行除以 5 的不幸影响，导致类不是 $Sum 列中的整数时出现问题。

lapply(ASWldtSUM,function(x[,3])(x/5))

具有仅返回单个向量的效果，如果这不是嵌套的数据帧数组，那么它会很好地工作，而是语句

ASWdtSUM$NEWCOL<-lapply(ASWldtSUM,function(x[,3])(x/5))

不能简单写，因为是嵌套的。

在以下语句中使用 rapply:

rapply(ASWldtSUM,function(x) if (is.integer(x)) {(x/5)})

导致结果困惑。

那么，有没有一种简单的方法可以将第 4 列附加到每个嵌套的 DataFrame，或者用该值除以 5 替换每个 DF(Sum)的第三列？

Answer 1

很简单，如果ASWldtSUM是包含数据框的列表的名字，那么你可以这样做:

lapply(ASWldtSUM,FUN=function(x) { x[,3]=x[,3]/5; return(x) })

基本上，您将(整个)第三列替换为将(整个)第三列除以五。

实践中:

> ASWldtSUM1=data.frame(Ethnicity=rep('ASW',10),Variant=c("ACCEPTOR","CDS","CGA_CNVWIN","CGA_MIRB","DELETE","DISRUPT","DONOR","FRAMESHIFT","INSERT","INTRON"), Sum=c(1,68,1000,0,0,0,0,0,1,54))
> #created a first data.frame (equal to your example)
> ASWldtSUM2=data.frame(Ethnicity=rep('ASW',10),Variant=c("ACCEPTOR","CDS","CGA_CNVWIN","CGA_MIRB","DELETE","DISRUPT","DONOR","FRAMESHIFT","INSERT","INTRON"), Sum=c(1,2,3,4,5,6,7,8,9,10))
> #created a second data.frame (with different values for the third column)
> ASWldtSUM=list(ASWldtSUM1,ASWldtSUM2)
> #created a list of data frames
> lapply(ASWldtSUM,FUN=function(x) { x[,3]=x[,3]/5; return(x) })
> #apply the function to divide third column to each nested data.frame
[[1]]
   Ethnicity    Variant   Sum
1        ASW   ACCEPTOR   0.2
2        ASW        CDS  13.6
3        ASW CGA_CNVWIN 200.0
4        ASW   CGA_MIRB   0.0
5        ASW     DELETE   0.0
6        ASW    DISRUPT   0.0
7        ASW      DONOR   0.0
8        ASW FRAMESHIFT   0.0
9        ASW     INSERT   0.2
10       ASW     INTRON  10.8

[[2]]
   Ethnicity    Variant Sum
1        ASW   ACCEPTOR 0.2
2        ASW        CDS 0.4
3        ASW CGA_CNVWIN 0.6
4        ASW   CGA_MIRB 0.8
5        ASW     DELETE 1.0
6        ASW    DISRUPT 1.2
7        ASW      DONOR 1.4
8        ASW FRAMESHIFT 1.6
9        ASW     INSERT 1.8
10       ASW     INTRON 2.0
> #desired result