仅按月份标记周日期 R

Question

我有一个df如下：

x = data.frame(retailer = c(2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2),
store = c(5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6),
week = c(2021100301, 2021092601, 2021091901, 2021091201, 2020082901, 2020082201, 2020081501, 2020080801, 2021080101, 2021072501, 2021071801,
  2021071101, 2020070401, 2020062701, 2020062001, 2020061301))

我有几周的值对应于日期，例如 2021100301 是 10/03/2021，2021071101 是 07/11/2020。我想添加一个额外的列，我可以在其中标记这些周的格式，其中 2021100301 是 10，因为它是 10 月，2021090301 将是 09，因为它是 9 月，依此类推。我想在专栏中的所有星期都这样做，基本上只是在单独的专栏中按月标记它们。我试图让输出为：

x = data.frame(retailer = c(2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2),
store = c(5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6),
week = c(2021100301, 2021092601, 2021091901, 2021091201, 2020082901, 2020082201, 2020081501, 2020080801, 2021080101, 2021072501, 2021071801,
  2021071101, 2020070401, 2020062701, 2020062001, 2020061301),
month = c(10, 09, 09, 09, 08, 08, 08, 08, 08, 07, 07, 07, 07, 06, 06 ,06))

我有办法做到这一点吗？谢谢

Answer 1

试试 substr

library(dplyr)
x %>% 
   mutate(month = as.numeric(substr(week, 5, 6)))

-输出

 retailer store       week month
1         2     5 2021100301    10
2         2     5 2021092601     9
3         2     5 2021091901     9
4         2     5 2021091201     9
5         2     5 2020082901     8
6         2     5 2020082201     8
7         2     5 2020081501     8
8         2     5 2020080801     8
9         2     6 2021080101     8
10        2     6 2021072501     7
11        2     6 2021071801     7
12        2     6 2021071101     7
13        2     6 2020070401     7
14        2     6 2020062701     6
15        2     6 2020062001     6
16        2     6 2020061301     6

Answer 2

这是另一种方法：逻辑：

删除最后两位数字
转换为 class 日期
获取月份

library(dplyr)
library(lubridate)
x %>% 
  mutate(month1 = gsub('.{2}$', '', week),
         month1 = month(ymd(month1)))

   retailer store       week month1
1         2     5 2021100301     10
2         2     5 2021092601      9
3         2     5 2021091901      9
4         2     5 2021091201      9
5         2     5 2020082901      8
6         2     5 2020082201      8
7         2     5 2020081501      8
8         2     5 2020080801      8
9         2     6 2021080101      8
10        2     6 2021072501      7
11        2     6 2021071801      7
12        2     6 2021071101      7
13        2     6 2020070401      7
14        2     6 2020062701      6
15        2     6 2020062001      6
16        2     6 2020061301      6

仅按月份标记周日期 R

labeling week dates just by the month R

label

r

date

dataframe