我有以下数据帧
FileNumber ReferralDate Status
1 510709784 2018-10-07 CLOSED
2 NA <NA> <NA>
3 510704781 2018-05-04 CLOSED
4 NA <NA> <NA>
5 NA <NA> <NA>
6 NA <NA> <NA>
这是数据帧的结构
'data.frame': 6 obs. of 3 variables:
$ FileNumber : int 510709784 NA 510704781 NA NA NA
$ ReferralDate: chr "2018-10-07" NA "2018-05-04" NA ...
$ Status : chr "CLOSED" NA "CLOSED" NA ...
当我尝试使用以下代码在FileNumber列或Status列中捕获NA
值时。但它似乎不起作用。为什么会发生这种情况
> df%>%filter(Status=="<NA>")
[1] FileNumber ReferralDate Status
<0 rows> (or 0-length row.names)
> df%>%mutate(Status=as.factor(Status))%>%filter(Status=="<NA>")
[1] FileNumber ReferralDate Status
<0 rows> (or 0-length row.names)
> df%>%filter(FileNumber=="NA")
[1] FileNumber ReferralDate Status
<0 rows> (or 0-length row.names)
library(dplyr)
df <- data.frame(FileNumber = c(510709784, NA, 510704781, NA, NA, NA),
ReferralDate = c("2018-10-07", NA, "2018-05-04", NA, NA, NA),
Status = c("CLOSED", NA, "CLOSED", NA, NA, NA),
stringsAsFactors = FALSE)
使用is.na()
指代NA
,而不是==
df %>% filter(is.na(Status))
FileNumber ReferralDate Status
1 NA <NA> <NA>
2 NA <NA> <NA>
3 NA <NA> <NA>
4 NA <NA> <NA>