You can use the following methods to select random rows from a data frame in R using functions from the package:

Method 1: Select Random Number of Rows

df %>% sample_n(5)

This function randomly selects 5 rows from the data frame.

Method 2: Select Random Fraction of Rows

df %>% sample_frac(.25)

This function randomly selects 25% of all rows from the data frame.

The following examples show how to use each method in practice with the following data frame in R:

#create data frame
df <- data.frame(team=c('A', 'B', 'C', 'D', 'E', 'F', 'G', 'H'),
                 points=c(10, 10, 8, 6, 15, 15, 12, 12),
                 rebounds=c(8, 8, 4, 3, 10, 11, 7, 7))

#view data frame
df

  team points rebounds
1    A     10        8
2    B     10        8
3    C      8        4
4    D      6        3
5    E     15       10
6    F     15       11
7    G     12        7
8    H     12        7

Example 1: Select Random Number of Rows

We can use the following code to randomly select 5 rows from the data frame:

library(dplyr)

#randomly select 5 rows from data frame
df %>% sample_n(5)

  team points rebounds
1    F     15       11
2    A     10        8
3    D      6        3
4    G     12        7
5    B     10        8

Notice that five rows are randomly selected from the data frame.

Example 2: Select Random Fraction of Rows

We can use the following code to randomly select 25% of all rows from the data frame:

library(dplyr)

#randomly select 25% of all rows from data frame
df %>% sample_frac(.25)

  team points rebounds
1    E     15       10
2    G     12        7

Since the original data frame had 8 total values, 25% of 8 is equal to 2.

Note: You can find the complete documentation for the sample_n and sample_frac functions in dplyr .

Additional Resources

The following tutorials explain how to perform other common operations in dplyr: