Published Jun 24, 2024
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In NumPy, the .log10() method is used to calculate the base-10 logarithm of each element in an array. It is primarily used in scientific computations and mathematical applications where logarithmic scaling is required.


numpy.log10(array, out=None, where=True)
  • array: An array-like structure containing the elements for which the base-10 algorithm will be applied.
  • out (Optional): The array where the result is to be stored. If not provided, a new array is created to store the results.
  • where (Optional): The condition (array of boolean values) that determines which elements will the method be applied on.
    • If the condition is True for a particular element, the logarithm is computed for that element.
    • If the condition is False for a particular element, the logarithm is not computed for that element and the original element is retained.
    • If not provided, the logarithm is computed for all elements.


The below example demonstrates the use of the .log10() method:

import numpy as np
result = np.log10([1e-15, -3., 10, 100])

The code above will generate the following output:

[-15. nan 1. 2.]

Note: Running the above code will result in a RuntimeWarning due to attempting to calculate the logarithm of a negative number, which is not a valid operation.

Codebyte Example

In this codebyte example, the .log10() method only computes the base-10 logarithm of positive elements in the array:

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