join functions (left_join, inner_join) in R Programming - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to perform a left join of df1 and df2 by the column 'id'.

R Programming

result <- [1](df1, df2, by = "id")

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

Ainner_join

Bmerge

Cleft_join

Dfull_join

Attempts:

3 left

💡 Hint

Common Mistakes

Using inner_join instead of left_join will drop unmatched rows from df1.

The left_join function keeps all rows from the first data frame and adds matching rows from the second.

2fill in blank

medium

Complete the code to perform an inner join of df1 and df2 by the column 'key'.

R Programming

result <- [1](df1, df2, by = "key")

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

Afull_join

Binner_join

Cright_join

Dleft_join

Attempts:

3 left

💡 Hint

Common Mistakes

Using left_join will keep all rows from df1, not just matching ones.

The inner_join function returns only rows with matching keys in both data frames.

3fill in blank

hard

Fix the error in the code to join df1 and df2 by the column 'user_id' using inner join.

R Programming

joined_data <- [1](df1, df2, by = "user_id")

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

Ainner_join

Bleft_join

Cmerge

Djoin

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'join' instead of 'inner_join' causes an error.

The correct function for inner join in dplyr is inner_join. The option join does not exist.

4fill in blank

hard

Complete the code to perform a left join of df1 and df2 by matching df1's 'id' column to df2's 'user_id' column.

R Programming

result <- left_join(df1, df2, by = c("[1]" = "[2]"))

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

Aid

Buser_id

Ckey

Dcust_id

Attempts:

3 left

💡 Hint

Common Mistakes

Using by='id' which won't match df2$user_id.

Using by=c('id','user_id') which requires same position columns.

When join columns have different names, use by = c("df1_col" = "df2_col").

5fill in blank

hard

Fill all three blanks to perform an inner join of df1 and df2 by 'id', handling column conflicts with suffixes '_left' and '_right'.

R Programming

result <- inner_join(df1, df2, by = "[1]", suffix = c("[2]", "[3]"))

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

Aid

B_left

C_right

D_orig

Attempts:

3 left

💡 Hint

Common Mistakes

Not specifying suffix leads to error if column names overlap.

Reversing the suffix order.

The suffix argument specifies suffixes for overlapping non-key columns: first for left df, second for right.