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polars

Fast in-memory DataFrame library for datasets that fit in RAM. Use when pandas is too slow but data still fits in memory. Lazy evaluation, parallel execution, Apache Arrow backend. Best for 1-100GB datasets, ETL pipelines, faster pandas replacement. For larger-than-RAM data use dask or vaex.

84

1.01x
Quality

81%

Does it follow best practices?

Impact

86%

1.01x

Average score across 3 eval scenarios

SecuritybySnyk

Passed

No known issues

SKILL.md
Quality
Evals
Security

Evaluation results

87%

2%

Log Data ETL Pipeline

Lazy evaluation and query optimization

Criteria
Without context
With context

Lazy CSV reading

100%

100%

Calls collect()

100%

100%

Filter before aggregation

100%

100%

Categorical for low-cardinality columns

0%

0%

Parquet output

100%

100%

Expression-based column references

100%

100%

Multiple filter args

66%

100%

No row iteration

100%

100%

No in-place assignment

100%

100%

Chained operations

50%

50%

group_by syntax

100%

100%

Pipeline log file

100%

100%

100%

Migrate Analytics Script from Pandas to Polars

Pandas to Polars migration patterns

Criteria
Without context
With context

group_by spelling

100%

100%

No reset_index

100%

100%

when/then/otherwise

100%

100%

with_columns for new columns

100%

100%

No Python apply/lambda

100%

100%

Expression-based filter

100%

100%

No row iteration

100%

100%

Polars import only

100%

100%

pl.col() references

100%

100%

Produces output CSV

100%

100%

73%

3%

Sales Performance Ranking Dashboard

Window functions and parallel column computation

Criteria
Without context
With context

over() for group stats

100%

100%

over() for ranking

100%

100%

Parallel with_columns

50%

50%

rechunk on concat

0%

0%

Categorical for region

0%

0%

No map_elements/apply

100%

100%

No row iteration

100%

100%

Parquet output

100%

100%

Expression-based

100%

100%

Functional chaining

50%

80%

Repository
K-Dense-AI/claude-scientific-skills
Evaluated
Agent
Claude Code
Model
Claude Sonnet 4.6

Table of Contents

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