Writing files

Common examples for writing tabular data in Fused.

Geospatial data?

For geospatial formats (GeoParquet, GeoTIFF, etc.), see Writing Geospatial Data.

CSV

@fused.udf
def udf():
    import pandas as pd
    df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4]})
    
    df.to_csv("s3://fused-users/fused/aman/my-data/output.csv", index=False)  # change to your own path
    
    return "Saved!"

Parquet

Parquet is the recommended format for tabular data - it's columnar, compressed, and fast.

@fused.udf
def udf():
    import pandas as pd

    path = "s3://fused-sample/demo_data/housing_2024.csv"
    df = pd.read_csv(path)
    df['price_per_area'] = round(df['price'] / df['area'], 2)
    
    output_path = "s3://fused-users/fused/aman/housing_processed.parquet"  # change to your own path
    df.to_parquet(output_path)

    return f"File saved to {output_path}"

JSON

@fused.udf
def udf():
    import pandas as pd
    df = pd.DataFrame({'col1': [1, 2], 'col2': [3, 4]})
    
    df.to_json("s3://fused-users/fused/aman/my-data/output.json")  # change to your own path
    
    return "Saved!"

Where to Save Files

Storage	Path Format	Best For
Fused home directory	s3://fused-users/fused/aman/path/file.parquet	Persistent storage, sharing
Mounted disk	/mnt/cache/file.parquet	Temporary files, caching
Your own S3	s3://bucket/file.parquet	Enterprise integration

See Cloud Storage for details on connecting your own buckets.