Pandas vs Polars: A Comprehensive Comparison

Introduction

Suppose that you are right in the middle of a data project, dealing with huge sets and attempting to find as many patterns as you can as quickly as possible. You grab for the usual data manipulation tool, but what if there is a best appropriate tool that will improve your work output? Switching to the less known data processor, Polars, which has only recently entered the market, yet stands as a worthy contender to the maxed out Pandas library. This article helps you understand pandas vs polars, how and when to use and shows the strengths and weaknesses of each data analysis tool.

Learning Outcomes

• Understand the core differences between Pandas vs Polars.
• Learn about the performance benchmarks of both libraries.
• Explore the features and functionalities unique to each tool.
• Discover the scenarios where each library excels.
• Gain insights into the future developments and community support for Pandas and Polars.

What is Pandas?

Pandas is a robust library for data analysis and manipulation in Python. It offers data containers such as DataFrames and Series, which allows users to carry out various analyses on available data with relative simplicity. Pandas operates as a highly flexible library built around an extremely rich set of functions; it also possesses a strong coupling to other data analysis libraries.

Key Features of Pandas:

• DataFrames and Series for structured data manipulation.
• Extensive I/O capabilities (reading/writing from CSV, Excel, SQL databases, etc.).
• Rich functionality for data cleaning, transformation, and aggregation.
• Integration with NumPy, SciPy, and Matplotlib.
• Broad community support and extensive documentation.

Example:

import pandas as pd

data = {'Name': ['Alice', 'Bob', 'Charlie'],
        'Age': [25, 30, 35],
        'City': ['New York', 'Los Angeles', 'Chicago']}
df = pd.DataFrame(data)
print(df)

Output:

      Name  Age         City
0    Alice   25     New York
1      Bob   30  Los Angeles
2  Charlie   35      Chicago

What is Polars?

Polars is a high-performance DataFrame library designed for speed and efficiency. It leverages Rust for its core computations, allowing it to handle large datasets with impressive speed. Polars aims to provide a fast, memory-efficient alternative to Pandas without sacrificing functionality.

Key Features of Polars:

• Lightning-fast performance due to Rust-based implementation.
• Lazy evaluation for optimized query execution.
• Memory efficiency through zero-copy data handling.
• Parallel computation capabilities.
• Compatibility with Arrow data format for interoperability.

Example:

import polars as pl

data = {'Name': ['Alice', 'Bob', 'Charlie'],
        'Age': [25, 30, 35],
        'City': ['New York', 'Los Angeles', 'Chicago']}
df = pl.DataFrame(data)
print(df)

Output:

shape: (3, 3)
┌─────────┬─────┬────────────┐
│ Name    ┆ Age ┆ City       │
│ ---     ┆ --- ┆ ---        │
│ str     ┆ i64 ┆ str        │
╞═════════╪═════╪════════════╡
│ Alice   ┆  25 ┆ New York   │
│ Bob     ┆  30 ┆ Los Angeles│
│ Charlie ┆  35 ┆ Chicago    │
└─────────┴─────┴────────────┘

Performance Comparison

Performance is a critical factor when choosing a data manipulation library. Polars often outperforms Pandas in terms of speed and memory usage due to its Rust-based backend and efficient execution model.

Benchmark Example:
Let’s compare the time taken to perform a simple group-by operation on a large dataset.

Pandas:

import pandas as pd
import numpy as np
import time

# Create a large DataFrame
df = pd.DataFrame({
    'A': np.random.randint(0, 100, size=1_000_000),
    'B': np.random.randint(0, 100, size=1_000_000),
    'C': np.random.randint(0, 100, size=1_000_000)
})

start_time = time.time()
result = df.groupby('A').sum()
end_time = time.time()
print(f"Pandas groupby time: {end_time - start_time} seconds")

Polars:

import polars as pl
import numpy as np
import time

# Create a large DataFrame
df = pl.DataFrame({
    'A': np.random.randint(0, 100, size=1_000_000),
    'B': np.random.randint(0, 100, size=1_000_000),
    'C': np.random.randint(0, 100, size=1_000_000)
})

start_time = time.time()
result = df.groupby('A').agg(pl.sum('B'), pl.sum('C'))
end_time = time.time()
print(f"Polars groupby time: {end_time - start_time} seconds")

Output Example:

Pandas groupby time: 1.5 seconds
Polars groupby time: 0.2 seconds

Advantages of Pandas

• Mature Ecosystem: Pandas, on the other hand, have been around for quite some time and, as such, have a stable, lush environment.
• Extensive Documentation: Flexible, full-featured and accompanied with good documentation.
• Wide Adoption: Active community of users; It has a very big fan base and is used widely in the data science field.
• Integration: They have impressive compatibility and interoperability with other top-tier libraries such as NumPy, SciPy, and Matplotlib.

Advantages of Polars

• Performance: Polars is optimized for speed and can handle large datasets more efficiently.
• Memory Efficiency: Uses memory more efficiently, making it suitable for big data applications.
• Parallel Processing: Supports parallel processing, which can significantly speed up computations.
• Lazy Evaluation: Executes operations only when necessary, optimizing the query plan for better performance.

When to Use Pandas and Polars

Let us now look into how to use pandas and polars.

Pandas

• When working on small to medium-sized datasets.
• When you need extensive data manipulation capabilities.
• When you require integration with other Python libraries.
• When working in an environment with extensive Pandas support and resources.

Polars

• When dealing with large datasets that require high performance.
• When you need efficient memory usage.
• When working on tasks that can benefit from parallel processing.
• When you need lazy evaluation to optimize query execution.

Key Differences of Pandas vs Polars

Let us now look into the table below for Pandas vs Polars.

Additional Use Cases

Pandas:

• Time Series Analysis: Most suitable for time series data manipulation, it incorporates specific functions that allow for resampling, rolling windows, and time zone conversion.
• Data Cleaning: includes powerful procedures for dealing also with missing values, duplicates, and type conversions of data.
• Merging and Joining: Data merging and joining and concatenation functions – features that allow passing data from different sources through a wide range of manipulations.

Polars:

• Big Data Processing: Efficiently handles large datasets that would be cumbersome in Pandas, thanks to its optimized execution model.
• Stream Processing: Suitable for real-time data processing applications where performance and memory efficiency are critical.
• Batch Processing: Ideal for batch processing tasks in data pipelines, leveraging its parallel processing capabilities to speed up computations.

Conclusion

If one preserves computationally heavy operations, Pandas best fits for per record computations and vice versa for Polars. Data manipulation in pandas is rich, flexible and well supported which makes it a reasonable and suitable choice in many data science context. While pandas offers a higher speed compared to NumPy, there exist a high performance data structure known as Polars, especially when dealing with large datasets and memory consuming operations. We appreciates these differences and advantages and believe that there is value in understanding the criteria based on which you want to make a decision about which study program is best for you.

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Ayushi Trivedi

My name is Ayushi Trivedi. I am a B. Tech graduate. I have 3 years of experience working as an educator and content editor. I have worked with various python libraries, like numpy, pandas, seaborn, matplotlib, scikit, imblearn, linear regression and many more. I am also an author. My first book named #turning25 has been published and is available on amazon and flipkart. Here, I am technical content editor at Analytics Vidhya. I feel proud and happy to be AVian. I have a great team to work with. I love building the bridge between the technology and the learner.