Accessing columns ($, []) in R Programming - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to access the 'age' column using the $ operator.

R Programming

ages <- data[1]age

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

A@

B[[

C[

D$

Attempts:

3 left

💡 Hint

Common Mistakes

Using [ or [[ instead of $ when the task asks for $ operator.

Using @ which is for S4 objects, not data frames.

The $ operator is used in R to access columns by name in a data frame.

2fill in blank

medium

Complete the code to access the 'name' column using double square brackets.

R Programming

names <- data[1]"name"]

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

A[[

B$

C[

D@

Attempts:

3 left

💡 Hint

Common Mistakes

Using single brackets [ which return a data frame, not a vector.

Using $ which is correct but not what the question asks.

Double square brackets [[ ]] are used to extract a single column as a vector by name.

3fill in blank

hard

Fix the error in accessing the 'score' column as a vector.

R Programming

scores <- data[1]"score"]

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

A[[

B$

C[

D@

Attempts:

3 left

💡 Hint

Common Mistakes

Using single brackets [ which returns a data frame, causing errors if vector expected.

Using $ which works but the syntax here expects [[ ].

Using [["score"]] extracts the column as a vector, which is the correct way here.

4fill in blank

hard

Complete the code to create a subset data frame with only the 'height' column.

R Programming

subset <- data[ , [1]]

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

A[

B$

C"height"

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Using $ inside brackets which is invalid syntax.

Using 1 instead of the column name string.

Using [ , "height"] selects the 'height' column as a data frame subset.

5fill in blank

hard

Fill both blanks to extract the 'weight' column as a vector from the data frame.

R Programming

weights <- data[1][2]weight

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

A[[

B"

C]

D$

Attempts:

3 left

💡 Hint

Common Mistakes

Using $ with quotes which is invalid syntax.

Forgetting to close the brackets.

Double brackets [["weight"]] extract the 'weight' column as a vector.