Select 数据基于一个月中的某一天，“如果日期小于一个月中的某一天”

Question

I have a dataset with a column date like this:

id	date
1	2018-02-13
2	2019-02-28
3	2014-01-23
4	2021-10-28
5	2022-01-23
6	2019-09-28

I want to select data that have a date lesser than 15th February

I tried an ifelse statement to define 15th february for each year in my database but i want to know if there is an easier way to do so !

Here's the result i'm expecting

id	date
1	2018-02-13
3	2014-01-23
5	2022-01-23

Thanks in advance

Answer 1

You could use lubridate

library(lubridate)
library(dplyr)

d %>% filter(month(date)<2 | (month(date)==2 & day(date)<=15))

Output:

  id       date
1  1 2018-02-13
2  3 2014-01-23
3  5 2022-01-23

Answer 2

This is a base R option. Using format check if the month/year is between January 1st and February 15th.

df[between(format(df$date, "%m%d"), "0101", "0215"),]

Output

  id       date
1  1 2018-02-13
3  3 2014-01-23
5  5 2022-01-23