NumPy Binary operations: invert() function

Last update on April 03 2023 12:31:21 (UTC/GMT +8 hours)

numpy.invert() function

The invert() function is used to compute bit-wise inversion, or bit-wise NOT, element-wise.

Some common applications of numpy.invert() include:
Image Processing: Inverting the bits in image data, such as creating a negative image by inverting the color channels or modifying the alpha channel of an image.
Cryptography: Applying bitwise NOT operations during encryption or decryption processes, especially in algorithms that involve bit manipulation.
Error Detection and Correction: Implementing error detection and correction algorithms that involve bitwise NOT operations on binary data.
Digital Signal Processing: Performing bitwise NOT operations on digital signals for various purposes, such as data scrambling or descrambling.

Syntax:

numpy.invert(x, /, out=None, *, where=True, casting=’same_kind’, order=’K’, dtype=None,
subok=True[, signature, extobj ]) = <ufunc 'invert'>

Parameter:

Name	Description	Required / Optional
x	Only integer and boolean types are handled.	Required
out	A location into which the result is stored. If provided, it must have a shape that the inputs broadcast to. If not provided or None, a freshly-allocated array is returned.	Optional
where	Values of True indicate to calculate the ufunc at that position, values of False indicate to leave the value in the output alone.	Optional
**kwargs	For other keyword-only arguments.

Return value:

out: [ndarray or scalar]
Result: This is a scalar if x is a scalar.

Example: Bitwise NOT operation with NumPy arrays and binary representation

import numpy as np
>>> np.invert(np.array([13], dtype=uint16))
array([65522], dtype=uint16)
>>> np.binary_repr(1, width=16)
'0000000000000001'
>>> np.binary_repr(65522, width=16)
'1111111111110010'

In the above example, the bitwise NOT operation is applied to a NumPy array containing a single unsigned 16-bit integer (13). The resulting array contains the inverted value (65522). To visualize the inversion, the numpy.binary_repr() function is used to display the binary representation of the input number (1) and the inverted output (65522), both with a fixed width of 16 bits. The input number has a binary representation of '0000000000000001', while the inverted output has a binary representation of '1111111111110010'.

Example: Bitwise NOT operation with signed integers and binary representation

import numpy as np
>>> np.invert(np.array([13], dtype=np.int8))
array([-14], dtype=int8)
>>> np.binary_repr(-14, width=8)
'11110010'

In the above code, the bitwise NOT operation is applied to a NumPy array containing a single signed 8-bit integer (13). The resulting array contains the inverted value (-14). To visualize the inversion, the numpy.binary_repr() function is used to display the binary representation of the output number (-14) with a fixed width of 8 bits. The inverted output has a binary representation of '11110010'.

Python Code Editor:

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