从日期获取月份

Question

我有这个小标题，上面有一堆日期，下面是小标题的示例。

library(tibble); library(lubridate)

c("25/10/1952", "27/05/1961", "07/11/1962", "20/12/1963", "15/01/1966", "12/02/1966", "12/05/1966", "11/11/1967", "14/01/1975", "17/10/1976", "05/11/1981", "03/11/1982", "14/11/1982", "12/10/1984", "24/12/1988", "26/10/1998", "11/11/2003", "14/12/2003") -> start

c("08/11/1952", "27/05/1961", "07/11/1962", "28/12/1963", "10/03/1966", "05/03/1966", "12/05/1966", "16/11/1967", "15/02/1975", "30/10/1976", "05/11/1981", "16/11/1982", "18/11/1982", "12/10/1984", "29/12/1988", "28/10/1998", "12/11/2003", "02/02/2004") -> finish

tibble(start = as.Date(dmy(start)), finish = as.Date(dmy(finish))) -> df

我需要获取任一列中包含的唯一月份。所以上面的输出将是这样的：

January, February, March, May, October, November, December

我怎样才能实现这个目标？

Answer 1

你可以做

> df[] = lapply(df, \(x) format(as.Date(x), "%B"))
> df
      start   finish
1   October November
2       May      May
3  November November
4  December December
5   January    March
6  February    March
7       May      May
8  November November
9   January February
10  October  October
11 November November
12 November November
13 November November
14  October  October
15 December December
16  October  October
17 November November
18 December February

数据：

df = data.frame(start = c("25/10/1952", "27/05/1961", "07/11/1962", "20/12/1963", "15/01/1966", "12/02/1966", "12/05/1966", "11/11/1967", "14/01/1975", "17/10/1976", "05/11/1981", "03/11/1982", "14/11/1982", "12/10/1984", "24/12/1988", "26/10/1998", "11/11/2003", "14/12/2003"), 
                finish = c("08/11/1952", "27/05/1961", "07/11/1962", "28/12/1963", "10/03/1966", "05/03/1966", "12/05/1966", "16/11/1967", "15/02/1975", "30/10/1976", "05/11/1981", "16/11/1982", "18/11/1982", "12/10/1984", "29/12/1988", "28/10/1998", "12/11/2003", "02/02/2004"))