keep rows in data that meet conditions based on previous rows

Question

I am trying to write some code to only keep rows in my data frame that:

have the same ID but different Dates.

Below is my current and desired application date.

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akrun · Accepted Answer · 2021-05-17T02:04:09.627

1

We can group by 'ID', filter the IDs with number of distinct 'Date' are greater than 1

library(dplyr)
df1 %>%
    group_by(ID) %>%
    filter(n_distinct(Date, na.rm = TRUE) > 1) %>%
    ungroup

Or in base R

subset(df1, ID %in% names(which(table(unique(df1[c('ID', 'Date')])$ID) > 1)))

edited May 17 '21 at 02:04

answered May 17 '21 at 01:44

akrun

1

Isn't the `n() > 1` redundant? You can't have `n_distinct(...) > 1` with 1 value. – thelatemail May 17 '21 at 02:03
@thelatemail you are right. thanks – akrun May 17 '21 at 02:04

1 Answers1