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.