ray-data

Files (3)

• SKILL.md
• integration.md · references/
• transformations.md · references/

SKILL.md (first lines)

# Ray Data - Scalable ML Data Processing

Distributed data processing library for ML and AI workloads.

## When to use Ray Data

**Use Ray Data when:**
- Processing large datasets (>100GB) for ML training
- Need distributed data preprocessing across cluster
- Building batch inference pipelines
- Loading multi-modal data (images, audio, video)
- Scaling data processing from laptop to cluster

**Key features**:
- **Streaming execution**: Process data larger than memory
- **GPU support**: Accelerate transforms with GPUs
- **Framework integration**: PyTorch, TensorFlow, HuggingFace
- **Multi-modal**: Images, Parquet, CSV, JSON, audio, video

**Use alternatives instead**:
- **Pandas**: Small data (<1GB) on single machine
- **Dask**: Tabular data, SQL-like operations
- **Spark**: Enterprise ETL, SQL queries

## Quick start

### Installation

```bash
pip install -U 'ray[data]'
```

### Load and transform data

```python
import ray

# Read Parquet files
ds = ray.data.read_parquet("s3://bucket/data/*.parquet")

# Transform data (lazy execution)
ds = ds.map_batches(lambda batch: {"processed": batch["text"].str.lower()})

# Consume data
for batch in ds.iter_batches(batch_size=100):
    print(batch)
```

### Integration with Ray Train

```python
import ray
from ray.train import ScalingConfig
from ray.train.torch import TorchTrainer

# Create dataset
train_ds = ray.data.read_parquet("s3://bucket/train/*.parquet")

def train_func(config):
    # Access dataset in training
    train_ds = ray.train.get_dataset_shard("train")

    for epoch in range(10):
        for batch in train_ds.iter_batches(batch_size=32):
            # Train on batch
            pass

# Train with Ray
trainer = TorchTrainer(
    train_func,
    datasets={"train": train_ds},
    scaling_config=ScalingConfig(num_workers=4, use_gpu=True)
)
trainer.fit()
```

## Reading data

### From cloud storage

```python
import ray

# Parquet (recommended for ML)
ds = ray.data.read_parquet("s3://bucket/data/*.parquet")

# CSV
ds = ray.data.read_csv("s3://bucket/data/*.csv")

# JSON
ds = ray.data.read_json("gs://bucket/data/*.json")

# Images
ds = ray.data.read_images("s3://bucket/images/")
```

### From Python objects

```python
# From list
ds = ray.data.from_items([{"id": i, "value": i * 2} for i in range(1000)])

# From range
ds = ray.data.range(1000000)  # Synthetic data

# From pandas
import pandas as pd
df = pd.DataFrame({"col1": [1, 2, 3], "col2": [4, 5, 6]})
ds = ray.data.from_pandas(df)
```

## Transformations

### Map batches (vectorized)

```python
# Batch transformation (fast)
def process_batch(batch):
    batch["doubled"] = batch["value"] * 2

From Clay-HHK/claude-config, MIT.