Row key design strategies in Hadoop - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a row key by concatenating user ID and timestamp.

Hadoop

row_key = user_id + [1] + timestamp

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

A_

B:

C-

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' can cause confusion with arithmetic operations.

Using '-' might be confused with negative numbers.

Using an underscore '_' is a common way to separate parts in a row key for readability and uniqueness.

2fill in blank

medium

Complete the code to reverse the timestamp string for better row key distribution.

Hadoop

reversed_ts = timestamp[::[1]1]

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

A{

B[

C(

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Using brackets without proper slice causes syntax error.

Using parentheses or braces is invalid for slicing.

The minus sign '-' is used as the step value in the slice [::-1] to reverse the string.

3fill in blank

hard

Fix the error in the code to create a salted row key for load balancing.

Hadoop

salt = str(hash(user_id) [1] 10)
salted_key = salt + '_' + user_id + '_' + timestamp

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

A+

B%

C**

D//

Attempts:

3 left

💡 Hint

Common Mistakes

Using '//' causes integer division but not remainder.

Using '+' or '**' causes type errors.

The modulus operator '%' is used to limit the salt value within a range.

4fill in blank

hard

Fill both blanks to create a set comprehension that combines user IDs with reversed timestamps to form row keys.

Hadoop

row_keys = {user_id[1] '_' + timestamp[::[2]1] for user_id, timestamp in data.items()}

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

A+

B.

C-

D*

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-' or '*' for string concatenation causes errors.

Omitting the step in slicing causes incorrect reversal.

Use '+' to concatenate strings and '-' as the step in slicing [::-1] for reversing the timestamp.

5fill in blank

hard

Fill all three blanks to create a filtered set of row keys where timestamp is greater than a threshold.

Hadoop

filtered_keys = {user_id[1] timestamp for user_id, timestamp in data.items() if timestamp [2] threshold and user_id[3] 'active'}

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

A+

B>

C==

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-' for string concatenation causes errors.

Using '=' instead of '==' in condition causes syntax errors.

Use '+' to concatenate strings, '>' to compare timestamp with threshold, and '==' to check if user_id equals 'active'.