Python:NumPy take()

The take() method returns elements from an array at specified indices, similar to standard indexing but applicable across flattened or specified axes for more flexible element selection.

Syntax

ndarray.take(indices, axis=None, out=None, mode='raise')

Parameters:

• indices: The 0-based indices of elements to extract.
• axis (Optional): Specifies the axis to take the elements. If not specified, the operation is done over a flattened array.
• out (Optional): An optional output array to store the selected elements. The shape and buffer length must match the expected output, but the type will be cast if necessary.
• mode (Optional): Specifies how out-of-bounds indices are handled:
  • raise: Raises an error (default).
  • wrap: Wrap around to the valid range.
  • clip: Clips to the valid range.

Return value:

Returns an array containing the selected elements, or a reference to out if specified.

Example

This example demonstrates how to use the take() method to extract elements by index:

import numpy as np

arr = np.array([10, 20, 30, 40, 50])
result = arr.take([0, 3, 4])
print(result)

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The output of this code is:

[10 40 50]

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Note: The take() method can only extract elements along a single axis and cannot select multi-dimensional index combinations in one call. For example:

import numpy as np

arr = np.array([[10, 20, 30],
                [40, 50, 60],
                [70, 80, 90]])

# Invalid: cannot take (0,0) and (1,1) in one call
arr.take([(0, 0), (1, 1)])  # Raises an error

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The above will return an error.

Codebyte Example

In this example, ndarray.take() is applied to a 2D array to extract rows, columns, and wrapped indices:

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