Subset n number of rows from a dataframe, based on a categorical variable, in R

Question

I have a dataframe (say x) in R:

> x
Height  Weight Gender
5     60    m
5     70    m
6     80    m
4     90    m
4     60    m
5     70    f
5     80    f
6     60    f
4     90    f
4     60    f

I need an R code that will produce a new dataframe, say y, that takes the subset of X by Gender and only the first three rows of each gender (1:3) to give the result as follows.

>y
Height  Weight Gender
5       60      m
5       70      m
6       80      m
5       70      f
5       80      f
6       60      f

Answer 1

Try slice from dplyr

library(dplyr)
x %>%
    group_by(Gender) %>% 
    slice(1:3)

Or using data.table

library(data.table)
setDT(x)[,.SD[1:3] , Gender]