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Pandas vs Polars: A Complete Comparison of Syntax, Speed, and Memory

··224 words·2 mins·

Polars reads CSVs 8x faster than pandas and uses 97% less memory. Is it worth learning?

Short answer: yes, especially for large data volumes. Concrete comparison with real benchmarks (1M rows):

Speed:

  • CSV reading: pandas 1.92s vs Polars 0.23s → 8.2x faster
  • Polars automatically parallelizes reading across multiple CPU cores

Memory:

  • Filter + group: pandas uses 44.4 MB vs Polars 1.3 MB → 97% less memory
  • Polars uses columnar storage and an optimized execution engine

Key syntax differences:

# Filter — pandas
df[df['age'] > 28]

# Filter — Polars
df.filter(pl.col('age') > 28)

Lazy evaluation (Polars’ superpower): with scan_csv() nothing executes until you call .collect(). Polars analyzes the entire query and optimizes it before running.

When to use each:

  • pandas: quick exploratory analysis, small projects, Python ecosystem compatibility
  • Polars: data engineering, large datasets, production pipelines that need performance

💡 Explanation in a nutshell
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Polars doesn’t replace pandas — it complements it. If your current pipeline runs slow or consumes too much RAM, Polars may be the change you need. The learning curve is gentle: the syntax is more explicit but very similar.

More information at the link 👇

Also published on LinkedIn.
Juan Pedro Bretti Mandarano
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Juan Pedro Bretti Mandarano