r - 将 R 中的列转换为日期时间类型 : as. POSIXct 返回 NA

Question

我在尝试将 char 类型的列转换为日期时间时遇到了困难。

 Date.Time  Lat Lon Base
<chr>   <dbl>   <dbl>   <chr>
4/1/2014 0:11:00    40.7690 -73.9549    B02512
4/1/2014 0:17:00    40.7267 -74.0345    B02512
4/1/2014 0:21:00    40.7316 -73.9873    B02512
⋮   ⋮   ⋮   ⋮
4/30/2014 23:31:00  40.7443 -73.9889    B02764
4/30/2014 23:32:00  40.6756 -73.9405    B02764
4/30/2014 23:48:00  40.6880 -73.9608    B02764

使用变异:

df <- mutate(df, Date.Time = as.POSIXct(Date.Time,
                 format = "%M/%D%/%Y% %H:%M%S"))

虽然 Date.Time 的类型已从 更改为 ，但整个列只是 NA。

Sys.getlocale() 的输出:

'LC_CTYPE=en_US.UTF-8;LC_NUMERIC=C;LC_TIME=C;LC_COLLATE=en_US.UTF-8;LC_MONETARY=en_US.UTF-8;LC_MESSAGES=C;LC_PAPER=en_US.UTF-8;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=en_US.UTF-8;LC_IDENTIFICATION=C'

Answer 1

您输入的格式代码不正确。应为 "%m/%d/%Y %H:%M:%S" 而不是 "%M/%D%/%Y% %H:%M%S “。其他一切都很好:

library(dplyr)

df <- read.table(header = TRUE, text = '
 Date.Time          Lat     Lon         Base
"4/1/2014 0:11:00"    40.7690 -73.9549    B02512
"4/1/2014 0:17:00"    40.7267 -74.0345    B02512
"4/1/2014 0:21:00"    40.7316 -73.9873    B02512
"4/30/2014 23:31:00"  40.7443 -73.9889    B02764
"4/30/2014 23:32:00"  40.6756 -73.9405    B02764
"4/30/2014 23:48:00"  40.6880 -73.9608    B02764')

df2 <- mutate(df, Date.Time = as.POSIXct(Date.Time, 
                                        format = "%m/%d/%Y %H:%M:%S"))

str(df2)
# 'data.frame': 6 obs. of  4 variables:
#   $ Date.Time: POSIXct, format: "2014-04-01 00:11:00" "2014-04-01 00:17:00" "2014-04-01 00:21:00" ...
# $ Lat      : num  40.8 40.7 40.7 40.7 40.7 ...
# $ Lon      : num  -74 -74 -74 -74 -73.9 ...
# $ Base     : chr  "B02512" "B02512" "B02512" "B02764" ...