Polars Series product() Method with Examples

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  • Post last modified:June 23, 2025
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In Polars, the Series.product() method is used to compute the product of all values within a Series. Similar to sum(), which adds elements, this method multiplies them together and returns the result.

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In this article, I will explain the product() method of the Polars Series, covering its syntax, parameters, and how it works. This method returns a single scalar value, either an int, float, or None if the Series is empty or contains only null values.

Key Points –

  • The product() method computes the multiplicative product of all non-null values in a Series.
  • The method returns a single scalar value: either int, float, or None.
  • Ignores null values by default while computing the product.
  • Returns None if the Series is empty or contains only nulls.
  • Zero values are included in the multiplication, and the result will be zero if any element is zero.
  • Handles negative numbers correctly; the sign of the result reflects the number of negative terms.

Polars Series product() Introduction

Let’s know the syntax of the series product() method.


# Syntax of product()
Series.product() → int | float

Parameters of the Polars Series product()

Computes the cumulative multiplication of all values in the Series.

Return Value

This function returns an int or float, depending on the data type. Ignores null values by default.

Usage of Polars Series product() Method

The product() method in Polars calculates the multiplicative result of all non-null values in a Series. It multiplies all the elements together to return their total product.

Now, let’s create a Polars Series.


import polars as pl

# Sample Series with nulls
ser = pl.Series("values", [2, 4, 6, 8])
print("Original Series:\n", ser)

Yields below output.

polars series product

To calculate the basic integer product of a Polars Series, you can use the product() method.


# Calculate the product of all values
ser2 = ser.product()
print("Product of values:", ser2)

Here,

  • The product is computed as: 2 × 4 × 6 × 8 = 384
  • product() returns a single scalar value, the result of multiplying all the non-null values in the Series.
polars series product

Series with Null Values

The product() method in Polars can handle Series containing null (or None) values. It computes the product using only the non-null elements, effectively ignoring any nulls in the Series.


import polars as pl

# Create a Series with some null values
ser = pl.Series("values", [2, None, 4, 6])

# Compute the product, ignoring nulls
ser2 = ser.product()
print("Product of non-null values:", ser2)

# Output:
# Product of non-null values: 48

Here,

  • Polars ignores nulls by default when computing the product.
  • The calculation is: 2 × 4 × 6 = 48
  • This behavior is similar to sum(), nulls are skipped unless all values are null.

Product with Zero in Series

If your Polars Series contains a zero, the product() method will return 0, since multiplying by zero nullifies the entire product, just like in mathematics.


import polars as pl

# Series with a zero
ser_with_zero = pl.Series("values", [2, 0, 6, 8])

# Compute product
ser2 = ser_with_zero.product()
print("Product of values:", ser2)

# Output:
# Product of values: 0

Here,

  • The product is: 2 × 0 × 6 × 8 = 0
  • Polars correctly returns 0 as the product, even if other values are non-zero.
  • This is standard behavior across numerical libraries.

Negative Numbers

When your Polars Series contains negative numbers, the product() method includes them in the multiplication, following standard arithmetic rules.


import polars as pl

# Series with negative numbers
ser_negative = pl.Series("values", [2, -3, 4])

# Compute product
ser2 = ser_negative.product()
print("Product of values:", ser2)

# Output:
# Product of values: -24

Here,

  • The product is calculated as: 2 × (-3) × 4 = -24
  • Polars correctly handles negative values and preserves the sign.
  • If you have an odd number of negative values, the result will be negative; if it’s even, the result will be positive.

Conclusion

In conclusion, the product() method in Polars provides a simple and effective way to calculate the multiplicative product of values in a Series. It gracefully handles null values, includes negative numbers as per arithmetic rules, and returns zero if any element is zero. This makes it a reliable choice for performing product-based aggregations in data analysis.

Happy Learning!!

References

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