R functions to trim data frame

below is a sample data frame and I would like to trim and data frame by extracting different columns:

> c1<-c(1:10)
> c2<-c(1,2,3,4,5,4,3,2,1,9)
> c3<-c(11:20)
> df<-data.frame(c1,c2,c3)
> df
   c1 c2 c3
1   1  1 11
2   2  2 12
3   3  3 13
4   4  4 14
5   5  5 15
6   6  4 16
7   7  3 17
8   8  2 18
9   9  1 19
10 10  9 20

Say if I wanna skip the entire top and bottom row, which shall be like:

Is there a function where I can extract the data frame or to eliminate certain rows? Thanks so much.

>Solution :

The dplyr package has multiple functions to assist with this

slice keeps the rows or requested (or removes those with a "-" in front of them)

df |>
  slice(-c(1, n()))

or equivalently,

slice(df, -c(1, n()))

filter let’s you keep the rows with specified conents

df |>
  filter(c1 > 1)

Commas act like "and" (so both requirements must be true)

df |>
  filter(
    c1 > 1,
    c3 < 20
  )