Row and column indexing in R Programming - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to select the first row of the data frame df.

R Programming

df[[1], ]

Drag options to blanks, or click blank then click option'

A0

Bdf

C1

Drow

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0 as the row index (R indexing starts at 1).

Using the data frame name instead of a row number.

In R, to select the first row of a data frame, you use df[1, ]. The number 1 specifies the first row.

2fill in blank

medium

Complete the code to select the column named age from the data frame df.

R Programming

df$[1]

Drag options to blanks, or click blank then click option'

Aage

B1

Cdf

Dcolumn

Attempts:

3 left

💡 Hint

Common Mistakes

Using a number instead of the column name after the dollar sign.

Putting quotes around the column name after the dollar sign.

To select a column by name in R, use the dollar sign $ followed by the column name, like df$age.

3fill in blank

hard

Fix the error in the code to select the element in the second row and third column of df.

R Programming

df[[1], 3]

Drag options to blanks, or click blank then click option'

A0

B2

C1

D3

Attempts:

3 left

💡 Hint

Common Mistakes

Using 3 as the row index instead of 2.

Using 0 as an index (R indexing starts at 1).

To select the element in the second row and third column, the row index should be 2. So the correct code is df[2, 3].

4fill in blank

hard

Fill both blanks to select rows where the score column is greater than 50.

R Programming

df[df$[1] [2] 50, ]

Drag options to blanks, or click blank then click option'

Ascore

B<

C>

Dage

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong column name.

Using the less than operator instead of greater than.

To select rows where the score column is greater than 50, use df[df$score > 50, ].

5fill in blank

hard

Fill all three blanks to create a new data frame new_df with only the name and age columns for rows where age is less than 30.

R Programming

new_df <- df[df$[1] [2] 30, c([3])]

Drag options to blanks, or click blank then click option'

Aage

B<

C"name", "age"

D"score", "age"

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong operator for comparison.

Selecting columns that are not name and age.

Not using quotes around column names inside c().

This code filters rows where age is less than 30 and selects only the name and age columns. The correct code is new_df <- df[df$age < 30, c("name", "age")].