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Polars explode multiple columns Vs Pandas explode multiple columns: A Comparison

10 May, 2023

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Introduction

Polars and pandas are popular python libraries for data manipulation and analysis. Both libraries offer an explode() function to break down a column with a list of values into separate rows for each value. However, polars and pandas have some differences in terms of syntax and performance. In this article, we will compare polars explode multiple columns and pandas explode multiple columns with code examples.

Prerequisite required

  • Python
  • Libraries required (pandas and polars)
  • Jupyter notebook or Google Colab

First let's see some differences between polars and pandas when it comes to exploding multiple columns:

  1. Syntax: Polars provides a more concise syntax for exploding multiple columns, as we can pass a list of column names directly to the df.explode() function. while, pandas requires us to define a custom function to apply the df.explode() function to each row.
  2. Performance: Polars is designed to handle large datasets and uses Rust, a compiled language, under the hood. This means that polars can be faster than pandas, especially for operations that involve large amounts of data. In addition, polars supports lazy evaluation, which means that computations are only performed when necessary, leading to faster processing times.
  3. Memory Usage: Polars uses less memory than pandas, especially for operations that involve large amounts of data. This is because polars stores data in a more efficient binary format, rather than in memory as pandas does.
  4. Handling Missing Data: Polars provides better support for handling missing data compared to pandas. Polars allows us to fill missing values with a default value, which is useful when we want to explode a column that contains missing values. In contrast, pandas requires us to replace missing values before exploding the column.
  5. Flexibility: Pandas provides more flexibility than polars in terms of customizing the exploding operation. For example, we can choose to explode a column only if it contains a certain value or has a certain length in pandas. In polars, we can't do this directly, but we can use filtering operations to achieve a similar result.

Overall Polars provide a more concise and intuitive syntax for exploding multiple columns, while pandas require more code to achieve the same result.

Polars Explode Multiple Columns

Polars is an open-source library for data manipulation and analysis, designed to handle large datasets. It offers a df.explode() function to break down a column with a list of values into separate rows for each value. To explode multiple columns in polars, we need to pass the column names as a list to the df.explode() function.
Here is an example of how to use polars explode multiple columns:

import polars as pl

df = pl.DataFrame({
    'id': [1, 2, 3],
    'name': ['Mercy', 'Tomi', 'Grace'],
    'hobbies': [['reading', 'cooking'], ['running'], ['traveling', 'baking']],
    'favorites': [['pizza', 'ice cream'], ['bread'], ['cake', 'hamburger']]
})

df_exploded = df.explode(['hobbies', 'favorites'])
df_exploded

Output:

In this example, we create a polars dataframe with four columns. The hobbies and favorites columns contain lists of values. We then use the df.explode() function to explode both the hobbies and favorites columns into separate rows for each value.

Pandas Explode Multiple Columns

Pandas is a popular python library for data manipulation and analysis. It offers a df.explode() function to break down a column with a list of values into separate rows for each value. To explode multiple columns in pandas, we need to use the df.apply() function to apply the df.explode() function to each row.
Here is an example of how to use pandas explode multiple columns:

import pandas as pd

df = pd.DataFrame({
'id': [1, 2, 3],
'name': ['Mercy', 'Tomi', 'Grace'],
'hobbies': [['reading', 'cooking'], ['running'], ['traveling', 'baking']],
'favorites': [['pizza', 'ice cream'], ['doughnut'], ['cake', 'bread']]
})

def explode_row(row):
row['hobbies'] = pd.Series(row['hobbies']).explode().reset_index(drop=True)
row['favorites'] = pd.Series(row['favorites']).explode().reset_index(drop=True)
return row

df_exploded = df.apply(explode_row, axis=1).explode('hobbies').explode('favorites')
df_exploded

Output:

In this example, we create a pandas dataframe with four columns. The hobbies and favorites columns contain lists of values. We then define a function explode_row() that applies the df.explode() function to each row, and use the df.apply() function to apply this function to each row. Finally, we use the df.explode() function to explode both the hobbies and favorites columns into separate rows for each value.

FAQs

  1. What is Polars explode multiple columns?

Polars is a blazingly fast data processing library written in Rust programming language. It provides a dataframe abstraction for manipulating tabular data. Polars explode multiple columns function allows you to transform a single row with multiple values in one or more columns into multiple rows with one value per row.

  1. What is Pandas explode multiple columns?

Pandas is a popular data manipulation library in python. Pandas explode multiple column function allows you to transform a single row with multiple values in one or more columns into multiple rows with one value per row.

  1. How do Polars explode multiple columns and Pandas explode multiple column differ?

Both polars explode multiple columns and pandas explode multiple column functions essentially do the same thing. However, polars is implemented in rust, which is a faster language than python, and hence polars is significantly faster than pandas. Polars also can perform operations in parallel, which makes it even faster than pandas.

  1. When should you use Polars explode multiple columns and Pandas explode multiple column?

If you are working with large datasets and need to perform operations on them, polars is recommended due to its speed and ability to perform operations in parallel. However, if you are working with smaller datasets, pandas is a good choice as it is easier to use and has a larger user community.

Conclusion

In summary, polars explode multiple columns and pandas explode multiple columns are two useful methods for exploding columns in a table. Polars is more convenient and perform better than pandas, but pandas provide more control over the exploded columns. The choice between the two depends on the specific requirements of the user's project. Thank you for reading!


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