从给定日期开始一周并在 R 中获取周数答案

【问题标题】：Start a week from given day and get week number in R从给定日期开始一周并在 R 中获取周数
【发布时间】：2022-01-16 18:03:11
【问题描述】：

让我们有一个日期序列，

df  = data.frame(date = seq(as.Date('2022-01-01'),as.Date('2022-01-31'),by = 1))

我想从 星期二 开始一周，然后剪切日期以创建新列 week 给出周数。所需的输出是，

date           week
1  2022-01-01    1
2  2022-01-02    1
3  2022-01-03    1
4  2022-01-04    2
5  2022-01-05    2

同样，如果我想从星期三开始这一周，预期的输出是，

date           week
1  2022-01-01    1
2  2022-01-02    1
3  2022-01-03    1
4  2022-01-04    1
5  2022-01-05    2
6  2022-01-06    2

我怎样才能完成这项工作？

如果一周从星期一开始，我会使用，

df%>% mutate(week = cut.Date(df$date, breaks = "1 week", labels = FALSE)) 
        date week
1  2022-01-01    1
2  2022-01-02    1
3  2022-01-03    2
4  2022-01-04    2
5  2022-01-05    2

感谢您的帮助...

【问题讨论】：

标签： r date lubridate week-number

【解决方案1】：

我们可以在floor_date 中指定week_start（week_start - 1 将是Monday 和7 将是Sunday）

f1 <- function(dates, wk_start = 1) {
    new <- lubridate::floor_date(dates, 'week', week_start = wk_start)
    match(new, unique(new))
}

-检查

> library(dplyr)
> df %>%
+    mutate(week = f1(date, wk_start = 1)) %>%
+    head
        date week
1 2022-01-01    1
2 2022-01-02    1
3 2022-01-03    2
4 2022-01-04    2
5 2022-01-05    2
6 2022-01-06    2
> df %>%
+    mutate(week = f1(date, wk_start = 2)) %>%
+    head
        date week
1 2022-01-01    1
2 2022-01-02    1
3 2022-01-03    1
4 2022-01-04    2
5 2022-01-05    2
6 2022-01-06    2
> df %>%
+    mutate(week = f1(date, wk_start = 3)) %>%
+    head
        date week
1 2022-01-01    1
2 2022-01-02    1
3 2022-01-03    1
4 2022-01-04    1
5 2022-01-05    2
6 2022-01-06    2

【讨论】：