How to Convert Index Arrays to One-Hot Encoded Arrays in NumPy?

One-Hot Encoding Index Arrays in NumPy

In NumPy, converting a 1D array of indices to a one-hot encoded 2D array is a common task. For example, given the array a with indices [1, 0, 3], we want to encode it as:

To achieve this, there are two key steps:

1. Create a zeroed array: Create a 2D array b with enough columns (i.e., a.max() 1) to accommodate the one-hot encoded values. The array should be initialized with zeros.
2. Set appropriate values to 1: For each row i in b, set the a[i]th column to 1. This indicates that the original index a[i] is present at position i in the one-hot encoded array.

Here's a code example to illustrate:

Output:

This method effectively converts the array of indices into a one-hot encoded array, where each row represents a one-hot encoded value of the corresponding index in a.

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