Select rows in a dataframe in r based on values in one row

Question

I have a toy data-frame.

a = rep(1:5, each=3)
b = rep(c(\"a\",\"b\",\"c\"), each = 5)
df = data.frame(a,b)

   a b
1  1 a
2  1 a
3  1 a
4  2 a
5  2 a
6  2 b
         


        

Answer 1

Use the %in% argument

df[df$a %in% idx,]