Question

我试图将数据框中的每一列从第一列转换为数字类型，我尝试过：

frames<-lapply(frames,function(x) {x[,2:ncol(x)]<-as.numeric(as.character(x[,2:ncol(x)]))} )

然而，这是用NAs取代所有东西

还试过

frames<-lapply(frames,function(x) {x[,2:ncol(x)]<-as.numeric(as.character(unlist(x[,2:ncol(x)]))  ) } )

然而，这种尝试并没有保留帧的结构

创建等效数据集的代码：

 test<-data.frame(Col1=c(1,2,3,4), Col2=c(2,4,5,5) , Col3=c(245,51,23,5) )
 test2<-data.frame(Col1= c(1,3,1,4), Col2= c(2,3,5,6) ,Col3= c(2,51,23,5))
 test[,2:3]<- lapply(test[,2:3], as.factor)
 test2[,2:3]<- lapply(test2[,2:3], as.factor)
 test_list<-list(test,test2)

现在两个帧都在test_list中，我想将每个测试数据帧的第二和第三列转换为数字类型。

dput(frames[[1]][1:5,1:5])

生成的数据集示例

 structure(list(date = c("04/03/13 - 10/03/13", "11/03/13 - 17/03/13",     
 "18/03/13 -   24/03/13", "25/03/13 - 31/03/13", "01/04/13 - 07/04/13"    ), 
`Summary Z: ` = c("12",     "9", "12", "10", "13"), `Summary O: ` = c("24",   
 "28", "24", "15", "17"), `Summary M: ` = c("3",     "4", "3", "2", "1"), 
 `Summary S: ` = c("2",     "2", "6", "3", "4")), .Names = c("date", "Summary Z: ",
 "Summary O: ",     "Summary M: ",     "Summary S: "    ), row.names = 7:11,
 class =   "data.frame")

Answer 1

您可以在lapply中使用list将factor列转换为numeric。在提供的示例中，first列除外，所有其他列都需要转换为numeric。在下面的代码中，通过x[,-1]取消选择第1列。通过使用lapply(x,[,-1],..)，它会将这些列转换为列表中的numeric。将<-分配给x[,-1]可恢复已转换列的原始data.frame结构。在最后一步中，return(x)或仅x将返回列表中的x data.frame。

 res <-  lapply(frames, function(x) {
             x[,-1] <- lapply(x[,-1], function(.x) as.numeric(as.character(.x)))
                   x})


 lapply(res,head,2)
 # [[1]]
 #  V1 V2 V3 V4 V5 V6
 #1  N 10 19 15  8  7
 #2  O 15  3 17  9  7

 # [[2]]
 #  V1 V2 V3 V4 V5 V6
 #1  K  1 12 14 13 13
 #2  O  3  4  1  5 17

使用test_list数据集

 res2 <- lapply(test_list, function(x) {
            x[,-1] <- lapply(x[,-1], function(.x) as.numeric(as.character(.x)))
                  x})



 str(res2)
 # List of 2
 #$ :'data.frame':  4 obs. of  3 variables:
 # ..$ Col1: num [1:4] 1 2 3 4
 #..$ Col2: num [1:4] 2 4 5 5
 #..$ Col3: num [1:4] 245 51 23 5
 #$ :'data.frame':  4 obs. of  3 variables:
 #..$ Col1: num [1:4] 1 3 1 4
 #..$ Col2: num [1:4] 2 3 5 6
 #..$ Col3: num [1:4] 2 51 23 5

更新

使用dput输出

 frames <- structure(list(date = c("04/03/13 - 10/03/13", "11/03/13 - 17/03/13",     
 "18/03/13 -   24/03/13", "25/03/13 - 31/03/13", "01/04/13 - 07/04/13"    ), 
`Summary Z: ` = c("12",     "9", "12", "10", "13"), `Summary O: ` = c("24",   
"28", "24", "15", "17"), `Summary M: ` = c("3",     "4", "3", "2", "1"), 
`Summary S: ` = c("2",     "2", "6", "3", "4")), .Names = c("date", "Summary Z: ",
"Summary O: ",     "Summary M: ",     "Summary S: "    ), row.names = 7:11,
 class =   "data.frame")

 frameslist <- list(frames, frames)
 frameslist <- lapply(frameslist, function(x) {
                          x[,-1] <- lapply(x[,-1], as.numeric)
                                x})

 str(frameslist[[1]])
 #'data.frame': 5 obs. of  5 variables:
 #$ date       : chr  "04/03/13 - 10/03/13" "11/03/13 - 17/03/13" "18/03/13 -   24/03/13" "25/03/13 - 31/03/13" ...
 # $ Summary Z: : num  12 9 12 10 13
 # $ Summary O: : num  24 28 24 15 17
 # $ Summary M: : num  3 4 3 2 1
 # $ Summary S: : num  2 2 6 3 4

转换列表中某些数据帧列的类型

1 个答案:

更新