我有一个数据框，其中的字符列有两种不同的日期格式，一种是mm/dd/yy，另一种是dd/mm/yyyy，所以我想使用lubridate来解析它们，并根据字符的数量进行调节。

x <- c("01/11/24", "17/11/2023", "02/25/24", "01/03/2022")
df <- as_tibble(x)
new_df <- df %>% mutate(value = if_else(nchar(value) == 8, mdy(value), dmy(value)))

字符串
这似乎会生成正确的日期列，但它会生成以下警告：

new_df
# A tibble: 4 × 1
  value     
  <date>    
1 2024-01-11
2 2023-11-17
3 2024-02-25
4 2022-03-01
Warning message:
There were 2 warnings in `mutate()`.
The first warning was:
ℹ In argument: `value = if_else(nchar(value) == 8, mdy(value), dmy(value))`.
Caused by warning:
!  1 failed to parse.
ℹ Run dplyr::last_dplyr_warnings() to see the 1 remaining warning. 
> dplyr::last_dplyr_warnings()
[[1]]
<warning/rlang_warning>
Warning in `mutate()`:
ℹ In argument: `value = if_else(nchar(value) == 8, mdy(value), dmy(value))`.
Caused by warning:
!  1 failed to parse.
---
Backtrace:
    ▆
 1. ├─df %>% ...
 2. ├─dplyr::mutate(...)
 3. └─dplyr:::mutate.data.frame(...)
[[2]]
<warning/rlang_warning>
Warning in `mutate()`:
ℹ In argument: `value = if_else(nchar(value) == 8, mdy(value), dmy(value))`.
Caused by warning:
!  1 failed to parse.
---
Backtrace:
    ▆
 1. ├─df %>% ...
 2. ├─dplyr::mutate(...)
 3. └─dplyr:::mutate.data.frame(...)

型
不知道警告告诉我什么，因为它声称1未能解析，但它似乎所有4解析正确。