Question

我想将第2列到第4列中的数值数据转换为日期。我可以逐列完成此操作，但不能一次完成所有操作。我认为它与那里的名称列有关，但我试图告诉R只是使用我想要的列。我究竟做错了什么？提前谢谢！

names<-c("tom", "dick", "harry", "mary", "susie")
date_1<-c(15127, 15034, 15034, 15141, 15013)
date_2<-c(15155, 15062, 15064, NA, 15041)
date_3<-c(15185, 15091, 15092, NA, 15069)
df<-data.frame(names, date_1, date_2, date_3)
df




as.Date(df$date_1, origin="1970-01-01")
[1] "2011-06-02" "2011-03-01" "2011-03-01" "2011-06-16" "2011-02-08"


as.Date(df[,2:4], origin="1970-01-01")
Error in as.Date.default(df[, 2:4], origin = "1970-01-01") : 
  do not know how to convert 'df[, 2:4]' to class “Date”

Answer 1

数据框是列表。使用lapply：

df[,-1] <- lapply(df[,-1],as.Date,origin = "1970-01-01")
> df
  names     date_1     date_2     date_3
1   tom 2011-06-02 2011-06-30 2011-07-30
2  dick 2011-03-01 2011-03-29 2011-04-27
3 harry 2011-03-01 2011-03-31 2011-04-28
4  mary 2011-06-16       <NA>       <NA>
5 susie 2011-02-08 2011-03-08 2011-04-05

将指定的列转换为R中的日期

1 个答案: