R Programming: Select Random Rows from a Given Data Frame

R Programming: Data frame Exercise-17 with Solution

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.

R Programming Code Editor:

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