NumPy TutorialLesson 5Free preview

NumPy Array Indexing

This lesson is part of NumPy · All levels

Summary

Indexing on the NumPy array allows access to both single and multiple elements at once. For a one-dimensional array, indexing is similar to Python list: arr[0] for the first element and arr[-1] for the last element. In a two-dimensional array, you use a row and column index like a[1, 2], and you can select multiple elements at once with the array as an index.

Key points

Indexing 1D array is the same as list: it starts from 0 and supports a negative index.
Indexing the 2D array using the index.
Can take many elements at once with np.array as an index.
Boolean arrays can be used as masks to select eligible elements.

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