Select index of data frame statisfying multiple conditions in R

Question

I have a data frame and I want to make make subset( or select only those rows) which satisfy the multiple conditions, Ex...

a <-data.frame(a=c("a","a","b","c","b","d"),b=c(1,2,3,4,2,3))
> a
  a b
1 a 1
2 a 2
3 b 3
4 c 4
5 b 2
6 d 3

I want to make subset where column a == a|b and column b = 2|3. Expected output

  a b
1 a 2
2 b 3
3 b 2  

I can do for one condition like

a[which(a[,"a"]=="a"),]

But is it possible to include all the multiple conditions in a single line?

Answer 1

a[(a$a %in% c('a', 'b')) & (a$b %in% c(2, 3)), ]

Answer 2

You can try using dplyr.

a <-data.frame(a=c("a","a","b","c","b","d"),b=c(1,2,3,4,2,3))

library(dplyr)
filter(a, (a == "a" | a == "b") & (b == 2 | b == 3))

Output:

  a b
1 a 2
2 b 3
3 b 2

Answer 3

subset(a, (a %in% c('a', 'b')) & (b %in% 2:3))