pocketflow/cookbook/pocketflow-batch-node/README.md

PocketFlow BatchNode Example

This example demonstrates the BatchNode concept in PocketFlow by implementing a CSV processor that handles large files by processing them in chunks.

What this Example Demonstrates

• How to use BatchNode to process large inputs in chunks
• The three key methods of BatchNode:
  1. prep: Splits input into chunks
  2. exec: Processes each chunk independently
  3. post: Combines results from all chunks

Project Structure

pocketflow-batch-node/
├── README.md
├── requirements.txt
├── data/
│   └── sales.csv      # Sample large CSV file
├── main.py            # Entry point
├── flow.py            # Flow definition
└── nodes.py           # BatchNode implementation

How it Works

The example processes a large CSV file containing sales data:

1. Chunking (prep): The CSV file is read and split into chunks of N rows
2. Processing (exec): Each chunk is processed to calculate:
   • Total sales
   • Average sale value
   • Number of transactions
3. Combining (post): Results from all chunks are aggregated into final statistics

Installation

pip install -r requirements.txt

Usage

python main.py

Sample Output

Processing sales.csv in chunks...

Final Statistics:
- Total Sales: $1,234,567.89
- Average Sale: $123.45
- Total Transactions: 10,000

Key Concepts Illustrated

1. Chunk-based Processing: Shows how BatchNode handles large inputs by breaking them into manageable pieces
2. Independent Processing: Demonstrates how each chunk is processed separately
3. Result Aggregation: Shows how individual results are combined into a final output