Convert an integer to binary without using the built-in bin function

Question

This function receives as a parameter an integer and should return a list representing the same value expressed in binary as a list of bits, where the first element in the l

Answer 1

You can use numpy package and get very fast solution:

python -m timeit -s "import numpy as np; x=np.array([8], dtype=np.uint8)" "np.unpackbits(x)"
1000000 loops, best of 3: 0.65 usec per loop

python -m timeit "[int(x) for x in list('{0:0b}'.format(8))]"
100000 loops, best of 3: 3.68 usec per loop

unpackbits handles inputs of uint8 type only, but you can still use np.view:

python -m timeit -s "import numpy as np; x=np.array([124567], dtype=np.uint64).view(np.uint8)" "np.unpackbits(x)"
1000000 loops, best of 3: 0.697 usec per loop