Reference library

Big data & Spark

PySpark jobs, partitioning, batch processing, and large-dataset transform patterns.

1 match
Big data & Spark easy

How to Implement collect_list in Python

Group rows by a key and collect all corresponding values into a list — a pure-Python mock of Spark's collect_list aggregation.

collect_list aggregation grouping
Python 
from collections import defaultdict

def collect_list(rows, key_field, value_field):
    grouped = defaultdict(list)
    for row in rows:
        grouped[row[key_field]].append(row[value_field])
    return dict(grouped)

if __name__ == "__main__":
    data = [
        {"dept": "sales", "emp": "alice"},
        {"dept"…
15 0 Open

Browse by section

Each section groups closely related Python snippets.

Big data & Spark — Python code examples

What you will find here

This page collects big data & spark snippets — short, copy-ready Python you can paste into our free online IDE and run without installing anything. Each sample includes a plain-English explanation and the full source code.

Samples vs tutorials and challenges

Samples are quick reference — one concept per page. For step-by-step teaching, use our Python tutorials. To test yourself, try quizzes or coding challenges. Clean up style with the Python formatter.

Related coding tools

Free online Python IDE Write and run Python in your browser — no install. Free Python code formatter Format with autopep8 — side-by-side PEP 8 cleanup. Python code samples Copy-ready snippets to study and run in the IDE.