Earliest Date for each id in R

Question

I have a dataset where each individual (id) has an e_date, and since each individual could have more than one e_date, I\'m trying to get the earli

Answer 1

I made a reproducible example, supposing that you grouped some dates by which quarter they were in.

library(lubridate)
library(dplyr)
rand_weeks <- now() + weeks(sample(100))
which_quarter <- quarter(rand_weeks)
df <- data.frame(rand_weeks, which_quarter)

df %>%
  group_by(which_quarter) %>% summarise(sort(rand_weeks)[1])

# A tibble: 4 x 2
  which_quarter sort(rand_weeks)[1]
                        
1             1 2017-01-05 05:46:32
2             2 2017-04-06 05:46:32
3             3 2016-08-18 05:46:32
4             4 2016-10-06 05:46:32