vaex

Process and analyze billion-row tabular datasets with lazy out-of-core DataFrames.

Updated Oct 7, 2022
One-click install
npx skills add https://github.com/tamagusko/linux-cfg --skill vaex-tamagusko
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: vaex
Source: https://github.com/tamagusko/linux-cfg/tree/main/dotfiles/claude/skills/vaex
Command: npx skills add https://github.com/tamagusko/linux-cfg --skill vaex-tamagusko

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill requires vaex, and includes references (resource) components.

What problem does it solve? Working with tabular datasets larger than available RAM causes pandas and similar tools to crash or force wasteful sampling. This Skill provides guidance for using Vaex to load, filter, aggregate, visualize, and run machine learning on datasets with billions of rows without loading them into memory. ## Core Features & Use Cases - Out-of-core DataFrames: Open HDF5, Arrow, Parquet, and CSV files instantly via memory mapping, with lazy evaluation and zero-copy virtual columns. - Fast aggregations and visualization: Compute statistics, groupby operations, and 1D/2D heatmap plots over billions of rows using batched delay=True execution. - ML pipelines at scale: Apply scalers, encoders, PCA, KMeans, and scikit-learn/XGBoost/LightGBM models, then save pipeline state for production deployment. - Use Case: Convert a 50GB CSV export to HDF5 once, then explore distributions, engineer features, and train an XGBoost model on the full dataset from a laptop. ## Quick Start Use the vaex skill to open my large HDF5 file, compute summary statistics by category, and plot a heatmap of two columns.

Frequently Asked Questions about vaex

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I process a CSV file larger than RAM in Python?

Use vaex.from_csv with chunk_size to stream the file, and pass convert='output.hdf5' to create a memory-mapped HDF5 copy. Future loads with vaex.open are instant and operations stay out-of-core.

What is the difference between Vaex and pandas for large datasets?

Vaex uses lazy evaluation and memory-mapped files so data never needs to fit in RAM, while pandas loads everything into memory. Vaex also supports virtual columns that compute on the fly with zero memory overhead.

Which file format works best with Vaex?

HDF5 and Apache Arrow are recommended because they are memory-mapped and load instantly. Parquet works well for distributed systems, while CSV should be converted to HDF5 for repeated use.

Can Vaex train machine learning models on big data?

Yes, vaex.ml provides scalers, encoders, PCA, and KMeans, plus wrappers for scikit-learn, XGBoost, LightGBM, CatBoost, and Keras. Transformations create virtual columns, and pipeline state can be saved to JSON for deployment.

Why is my Vaex aggregation slow across many columns?

Each aggregation without delay=True makes a separate pass through the data. Pass delay=True to each aggregation and combine them with vaex.execute so all statistics compute in a single pass.

When should I not use Vaex?

Avoid Vaex for small datasets that fit comfortably in memory, where pandas is simpler, and for workflows requiring row-by-row iteration, since Vaex is designed for vectorized column operations.