Add data transformations example demonstrating core Daft operations

[Copilot]

New example showcasing fundamental Daft data transformation patterns for newcomers.

Changes

• New example: usage_patterns/data_transformations/explore_filter_aggregate.py

  • Schema exploration, filtering, column transformations with when/otherwise, groupby aggregations, sorting
  • Self-contained sample emotion dataset (no external dependencies)
  • Contributor: GitHub Copilot

• README: Added Data Transformations section

Example usage

from daft import col
from daft.functions import when

df_transformed = (
    df
    .with_column("text_length", col("text").str.length())
    .with_column("word_count", col("text").str.split(" ").list.length())
    .with_column(
        "label_name",
        when(col("label") == 0, "sadness")
        .when(col("label") == 1, "joy")
        .otherwise("other")
    )
)

stats = (
    df_transformed
    .groupby("label_name")
    .agg(
        col("text").count().alias("count"),
        col("text_length").mean().alias("avg_length"),
    )
)

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• astral.sh
  • Triggering command: /usr/bin/curl curl -LsSf REDACTED (dns block)
• daft.gateway.scarf.sh
  • Triggering command: /usr/bin/python python usage_patterns/data_transformations/explore_filter_aggregate.py (dns block)
  • Triggering command: /usr/bin/python python -c import daft; from daft import col; df = daft.from_pydict({'text': ['hello', 'world']}); help(col('text').str) (dns block)
  • Triggering command: /usr/bin/python python -c import daft; from daft import col; df = daft.from_pydict({'text': ['hello', 'world']}); print(df.with_column('len', col('text').str.length()).collect()) (dns block)
• huggingface.co
  • Triggering command: /usr/bin/python python usage_patterns/data_transformations/explore_filter_aggregate.py (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

I want you build me a new example from scratch. Include yourself as the contributor. Welcome to the team.

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