CSV Dataset to Parquet for Machine Learning

Large training CSV files are slow to load and lose their types every time. Parquet fixes both.

Open the CSV to Parquet converter and drop the dataset with type detection on. Numeric features become numbers, dates become dates, and ids and labels can stay text.

Parquet keeps a type for every column, so set numbers, dates and text before you export, and read the file back to check it.

Before you train, use the Data Profiler to find blanks, duplicates and stray values, and keep the original CSV so any change can be traced. Load the Parquet in your notebook and compare the shape.

Everything runs in your browser and nothing is uploaded.

Open the CSV to Parquet converter

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How to use the CSV to Parquet converter: step by step

Open the CSV to Parquet converter.
Drop the dataset with type detection on.
Profile the data.
Download Parquet and check the shape.

When to use the CSV to Parquet converter

Speed up loading of a training set
Keep types between runs
Shrink a large dataset
Share data with a team

Example

Input: id,name,age 1,Ada,36 2,Alan,41

Output: A Parquet file with the same columns (id, name, age) and typed values.

Frequently asked questions

How do I convert CSV to Parquet?

Drop your CSV file (or paste the data), check the options, click Convert and download the Parquet result.

How big can a file be?

It depends on your device. A few hundred MB usually works.

Which conversions does the Format Converter support?

Any direction between JSON, CSV, Parquet and Excel (.xlsx), for one file or a whole folder. Nested JSON is flattened into columns such as address.city. For Excel, the first sheet is read; old .xls files are not supported.

Why did my number or date change after converting?

Types are detected from the values. Turn off "Detect types" to keep everything as text, which also keeps leading zeros in IDs and phone numbers.

Tip: Keep the original CSV so every change is traceable.