CODEWITHSUNDEEP
pythonarraysnumpy
Bartlomiej Lewandowski
Bartlomiej Lewandowski

Reputation: 11170

Convert numpy int array to boolean array

I have an array that maps the cells in a game of life. So far I have an int for every single cell. To minimize the amount of reads I want to compress the array to whole 8 cells per 1 integer.

The problem arises when I want to create a bitmap, which expects an array of 0 and 1 like in the previous case.

Is there any quick way in numpy to convert this? I could you a loop for this but there might be a better way.

Example:

[01011100b, 0x0] -> [0, 1, 0, 1, 1, 1, 0 ,0, 0,0,0,0,0,0,0,0]

Upvotes: 2

Views: 4607

Answers (1)

user2357112
user2357112

Reputation: 280182

numpy.packbits and numpy.unpackbits are a pretty close match for what you're looking for:

>>> numpy.packbits([1, 1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 1, 1])
array([225, 184], dtype=uint8)
>>> numpy.unpackbits(array([225, 184], dtype=numpy.uint8))
array([1, 1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 0, 0], dtype=uint8)

Note that numpy.unpackbits(numpy.packbits(x)) won't have the same length as x if len(x) wasn't a multiple of 8; the end will be padded with zeros.

Upvotes: 2

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