r语言 - 我如何得到每个月的数字?

Question

我有一个包含一列日期对象的数据框架。我怎样才能得到一个月的数字的新列?例如:January ->2月1日->2…

我还需要一个包含每月每天数字的新列。示例:2022-01-01 ->1、2022-01-02 - 2

Answer 1

您可以使用以下代码:

df = data.frame(date = as.Date(c("2022-01-01", "2022-01-02")))
df[, "month"] <- format(df[,"date"], "%m")
df

输出:

date month
1 2022-01-01    01
2 2022-01-02    01

Answer 2

我确信R中有特定于日期对象的解决方案，但我从未使用过它们。基数R解:

splitDates <- function( date ) {

day <- gsub('^0+','',unlist(strsplit(date,'-'))[2])
month <- gsub('^0+','',unlist(strsplit(date,'-'))[3])

return(list(day,
month))

}

Answer 3

require(tidyverse)
require(lubridate) 

示例数据:

# A tibble: 13 × 1
date      
<date>    
1 2022-04-28
2 2022-05-28
3 2022-06-28
4 2022-07-28
5 2022-08-28
6 2022-09-28
7 2022-10-28
8 2022-11-28
9 2022-12-28
10 2023-01-28
11 2023-02-28
12 2023-03-28
13 2023-04-28

一个可能的解决方案:

df %>%
mutate(
month = month(date),
month_name = month(date, label = TRUE, abbr = FALSE),
day = day(date),
week = week(date)
)

输出:

# A tibble: 13 × 5
date       month month_name   day  week
<date>     <dbl> <ord>      <int> <dbl>
1 2022-04-28     4 April         28    17
2 2022-05-28     5 May           28    22
3 2022-06-28     6 June          28    26
4 2022-07-28     7 July          28    30
5 2022-08-28     8 August        28    35
6 2022-09-28     9 September     28    39
7 2022-10-28    10 October       28    43
8 2022-11-28    11 November      28    48
9 2022-12-28    12 December      28    52
10 2023-01-28     1 January       28     4
11 2023-02-28     2 February      28     9
12 2023-03-28     3 March         28    13
13 2023-04-28     4 April         28    17