44. Item Positions in a Basket (POSEXPLODE)

Difficulty: Medium · Topics: Arrays, Filtering & Selection

Each row of baskets has an order_id and items, an array in the order the items were scanned.

Return one row per item: order_id, position (1 for the first item) and item. Orders with an empty or missing basket produce no rows.

Row order does not matter; column names must match. Your code is graded on 3 test cases, including hidden edge cases.

Sample data

baskets

order_id	items
1	[milk, bread, eggs]
2	[tea]

Expected output

order_id	position	item
1	1	milk
1	2	bread
1	3	eggs
2	1	tea

Hints

Hint 1

F.explode loses the position; F.posexplode returns it as well (0-based).

Hint 2

Name both outputs: F.posexplode("items").alias("pos", "item").

Hint 3

Add 1 to make positions start at 1.

PySpark functions you'll practise

• posexplode
• select

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Topics: Window Functions · Joins · Aggregations · Pivot, Unpivot & Rollup · Arrays · Null Handling · Conditional Logic · Dates · Filtering & Selection · Strings

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