R Programming: Select Random Rows from a Given Data Frame

Last update on June 04 2025 12:53:20 (UTC/GMT +8 hours)

Write a R program to select some random rows from a given data frame.

Sample Solution:

R Programming Code:

# Create a data frame with columns: name, score, attempts, and qualify
exam_data = data.frame(
  # Define the 'name' column
  name = c('Anastasia', 'Dima', 'Katherine', 'James', 'Emily', 'Michael', 'Matthew', 'Laura', 'Kevin', 'Jonas'),
  # Define the 'score' column
  score = c(12.5, 9, 16.5, 12, 9, 20, 14.5, 13.5, 8, 19),
  # Define the 'attempts' column
  attempts = c(1, 3, 2, 3, 2, 3, 1, 1, 2, 1),
  # Define the 'qualify' column
  qualify = c('yes', 'no', 'yes', 'no', 'no', 'yes', 'yes', 'no', 'no', 'yes')
)

# Print a message indicating the display of the original dataframe
print("Original dataframe:")
# Print the content of the original dataframe
print(exam_data)

# Print a message indicating that we will select three random rows
print("Select three random rows of the said dataframe:")
# Sample three random rows from the dataframe and print the result
print(exam_data[sample(nrow(exam_data), 3),])

Output:

[1] "Original dataframe:"
        name score attempts qualify
1  Anastasia  12.5        1     yes
2       Dima   9.0        3      no
3  Katherine  16.5        2     yes
4      James  12.0        3      no
5      Emily   9.0        2      no
6    Michael  20.0        3     yes
7    Matthew  14.5        1     yes
8      Laura  13.5        1      no
9      Kevin   8.0        2      no
10     Jonas  19.0        1     yes
[1] "Select three random rows of the said dataframe:"
      name score attempts qualify
10   Jonas  19.0        1     yes
7  Matthew  14.5        1     yes
4    James  12.0        3      no

Explanation:

Create Data Frame:

exam_data = data.frame(...):

This line creates a data frame named exam_data with four columns: name, score, attempts, and qualify.
name column contains names of individuals.
score column contains their scores.
attempts column contains the number of attempts.
qualify column contains whether they qualify ('yes' or 'no').

Print Original Data Frame:

print("Original dataframe:"):

Prints a message indicating the display of the original data frame.

print(exam_data):

Prints the entire exam_data data frame.

Print Random Rows:

print("Select three random rows of the said dataframe:"):

Prints a message indicating that three random rows will be selected.

print(exam_data[sample(nrow(exam_data), 3),]):

sample(nrow(exam_data), 3):

Randomly selects three row indices from the total number of rows in exam_data.

exam_data[...]:

Retrieves and prints the rows corresponding to the selected indices.

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R Programming Code Editor:

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