Count Rows per City

PYSPARK coding challenge · Difficulty: easy · Topic: GroupBy Aggregations · +50 XP

Problem

Return df_result with each city and the number of employees in it, column named count. Order by city ascending.

Example Input - `employees`

| name | city |
| --- | --- |
| Asha | Pune |
| Ravi | Delhi |
| Meera | Pune |

Expected Output

| city | count |
| --- | --- |
| Delhi | 1 |
| Pune | 2 |

Notes

• The DataFrame is created for you - do not recreate it
• Build a DataFrame called df_result and finish with df_result.show()

What this PYSPARK challenge teaches you

“Count Rows per City” is a easy-level PYSPARK challenge focused on GroupBy Aggregations. Working through it gives you hands-on practice with beginner — the kind of transformation you are asked to write in real data engineering work and in technical interviews. You can solve it directly in the browser: the dataset is pre-loaded, so you write the query or DataFrame code, run it, and compare your output against the expected result immediately.

Concepts covered

• beginner

How to approach it

If you get stuck, work through these steps in order before looking at a full solution — each one narrows the problem down:

1. groupBy() followed by count() gives one row per group with a count column.
2. employees.groupBy('city').count(), then .orderBy('city') so the rows come out in a fixed order.

How to practise it on PySpark.in

Open the challenge, write your PySpark code in the editor and press Run to execute it against the sample dataset. Submitting checks your output against every test case, including hidden ones, so you find out straight away whether your logic holds up. You can retry as often as you like, and each solved challenge adds to your XP.

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Frequently asked questions

Do I need to install Spark or a database to solve this?

No. The PYSPARK environment runs in your browser with the sample data already loaded, so there is nothing to install or configure.

Is this challenge free?

Yes - the problem, the sample dataset, the hints and unlimited test runs are free.

What level is it?

It is rated easy and covers GroupBy Aggregations.

Solve this challenge free on PySpark.in