How to find the cumulative product of a 2D array in Python

Overview

In Python, we can find the cumulative product of array elements using the cumprod() method from the NumPy library.

The numpy.cumprod() method

The numpy.cumprod() method returns the cumulative product of elements in a given input array over a specified axis.

Note: A two-dimensional (2D) array can be created using a list of lists in Python.

Syntax

numpy.cumprod(arr, axis=None, dtype=None, out=None)

Parameters

• arr: This is the input array.
• axis: This is an optional parameter. It represents the axes along which the operation is to be performed.
• dtype: This is an optional parameter. It represents the return type of the array.
• out: This is an optional parameter. It represents the alternative output array in which the result is to be placed.

Return value

The value returned is the cumulative product of the elements in the given input array over a specified axis.

Note: If the out parameter is specified, it returns an array reference to out.

Code

The following code shows how to find the cumulative product of the two-dimensional (2D) array using the numpy.cumprod() method.

Explanation

• Line 2: We import the numpy library.
• Lines 4–5: We create two lists, namely my_list1 and my_list2.
• Line 7: We convert the lists to a NumPy array which gives us a 2D array. We then store the value in a variable called np_list.
• Line 10: We use the np.cumprod() to compute the cumulative product of elements in the np_list and store it in np_list_cumprod.
• Line 11: We display the result.