R-如何将空的POSIXct列添加到数据中。帧/TIBLE已存在?

这对你有用吗(大多数人按照eipi10中的建议去做) his comment )

library(tibble) # install.packages(c("dplyr"), dependencies = TRUE)
df <- tibble(a = 1:3, b = letters[a], c = as.POSIXct(NA))

df 
#> # A tibble: 3 x 3
#>       a     b      c
#>   <int> <chr> <dttm>
#> 1     1     a     NA
#> 2     2     b     NA
#> 3     3     c     NA

str(df)
#> Classes ‘tbl_df’, ‘tbl’ and 'data.frame':
#>    3 obs. of  3 variables:
#> $ a: int  1 2 3
#> $ b: chr  "a" "b" "c"
#> $ c: POSIXct, format: NA NA ...

df <- tibble(a = numeric(), b = character(), c = as.POSIXct(NA))
str(df)
#> Classes ‘tbl_df’, ‘tbl’ and 'data.frame':
#>   0 obs. of  3 variables:
#> $ a: num 
#> $ b: chr 
#> $ c:Classes 'POSIXct', 'POSIXt'  num(0)