Filter rows that meet two differential conditions-CodePudding

I'm looking for elegant code which filter rows that meet two conditions in a differential way, to a new df:

filter (birth_year==1987 & graduation_year==2005)
       (birth_year==1990 & graduation_year==2008)
       (birth_year==1993 & graduation_year==2011)
       (birth_year==1998 & graduation_year==2016)
#this is not a code

Here is my df:

birth_year <- c(1987,1987,1987,1990,1990,1990,1993,1993,1998,1998)
graduation_year <- c(2005,2005,2006,2008,2007,2008,2011,2012,2017,2016)
grade<-c(56,101,85,120,75,96,85,68,91,105)

df <- data.frame(birth_year, graduation_year, grade)

> df
   birth_year graduation_year grade
1        1987            2005    56
2        1987            2005   101
3        1987            2006    85
4        1990            2008   120
5        1990            2007    75
6        1990            2008    96
7        1993            2011    85
8        1993            2012    68
9        1998            2017    91
10       1998            2016   105

the result/the new df should be:

   birth_year graduation_year grade
1        1987            2005    56
2        1987            2005   101
3        1990            2008   120
4        1990            2008    96
5        1993            2011    85
6        1998            2016   105

CodePudding user response：

In this specific case I think you could do it like this:

filter(graduation_year - birth_year == 18)

Another idea is creading a reference dataframe with your conditions like this:

birth_year <- c(1987, 1990, 1993, 1998)
graduation_year <- c(2005, 2008, 2011, 2016)

conditions <- data.frame(birth_year, graduation_year)

And then applying inner_join:

df %>% inner_join(conditions)

Joining, by = c("birth_year", "graduation_year")
  birth_year graduation_year grade
1       1987            2005    56
2       1987            2005   101
3       1990            2008   120
4       1990            2008    96
5       1993            2011    85
6       1998            2016   105

CodePudding user response：

You can use the %in% operator

library(dplyr)

new_df <- df %<%
  filter(birth_year %in% c(1987, 1990, 1993, 1998),
         graduation_year  %in% c(2005, 2008, 2011, 2016)
         )

CodePudding user response：

You can simply separate your conditions with | so that you keep all of the records that meet either of them.

library(dplyr)

new_df <- df %>% filter(birth_year==1987 & graduation_year==2005 | 
       birth_year==1990 & graduation_year==2008 |
       birth_year==1993 & graduation_year==2011 | 
       birth_year==1998 & graduation_year==2016)