R从列中的日期获取最小和最大的问题

Question

我试图从一列中的一组日期中获得最小和最大值。当我运行下面的代码时，我在查找最小值时得到了第一个条目的最大日期(其余的都是ok的)，在查找最大值时得到了第一个条目的最大条目的最小日期(其余的都是ok的)。

数据:

structure(list(PR.Number = structure(c(1L, 1L, 2L, 2L, 3L, 3L
), .Label = c("PR1234", "PR1235", "PR1236", "PR1237", "PR1238"
), class = "factor"), Date.received = structure(c(2L, 1L, 7L, 
10L, 8L, 9L), .Label = c("01/02/2024", "05/01/2022", "09/09/2023", 
"09/09/2025", "10/03/2023", "10/03/2024", "15/07/2022", "16/11/2022", 
"16/11/2023", "30/09/2022"), class = "factor")), row.names = c(NA, 
6L), class = "data.frame")

代码马克斯:

R_Date.Test %>% 
group_by(PR.Number) %>% 
slice_max(Date.received)

代码分钟:

R_Date.Test %>% 
group_by(PR.Number) %>% 
slice_min(Date.received)

最小输出:PR.Number Date.received

1 PR1234 01/02/2024 2 PR1235 15/07/2022
3 PR1236 16/11/2022
4 PR1237 10/03/2023
5 PR1237 10/03/2023
6 PR1238 09/09/2023

Max输出:PR.Number Date.received

1 PR1234 05/01/2022 2 PR1235 30/09/2022
3 PR1236 16/11/2023
4 PR1237 10/03/2024
5 PR1238 09/09/2025

Answer 1

您的Date.received是一个因子而不是Date对象所以试试:

R_Date.Test$Date.received <-  as.Date(df$Date.received , "%d/%m/%Y")
# then apply your code above
R_Date.Test %>% 
group_by(PR.Number) %>% 
slice_min(Date.received)