docs/how-tos/compute-to-data/make-a-boss-c2d-algorithm.md

---
description: >-
  How to construct the beginnings of an awesome algorithm for C2D compute jobs
  on datasets
---

# Make a Boss C2D Algorithm

{% embed url="https://media3.giphy.com/media/cub3pntkz8muQ/giphy.gif?cid=ecf05e47o9fdrqco4jqpeyh7899whqgw5tnd43elr023rykr&ep=v1_gifs_search&rid=giphy.gif" %}

The beginning of any great algorithm for Compute-to-Data first starts by referencing the dataset file correctly on the Docker image. Here is the code in Javascript and in Python for how to correctly reference the dataset file that's local on the Docker container that you choose:

### Python

```
import csv
import json
import os

def get_input(local=False):

    dids = os.getenv("DIDS", None)

    if not dids:
        print("No DIDs found in the environment. Aborting.")
        return

    dids = json.loads(dids)

    for did in dids:
        filename = f"data/inputs/{did}/0"  # 0 for metadata service
        print(f"Reading asset file {filename}.")
        return filename

# Get the input filename using the get_input function
input_filename = get_input()

if not input_filename:
    # No input filename returned
    exit()
    
# Call the Function
with open(input_filename, 'r') as file:
    # Read the CSV file
    csv_reader = csv.DictReader(file)
    
    <The rest of your code goes here>
```

### Javascript