numpy.binary_repr()

numpy.binary_repr(num, width=None) [source]

Return the binary representation of the input number as a string.

For negative numbers, if width is not given, a minus sign is added to the front. If width is given, the two?s complement of the number is returned, with respect to that width.

In a two?s-complement system negative numbers are represented by the two?s complement of the absolute value. This is the most common method of representing signed integers on computers [R16]. A N-bit two?s-complement system can represent every integer in the range $-2^{N-1}$ to $+2^{N-1}-1$ .

Parameters:

Parameters:	num : int Only an integer decimal number can be used. width : int, optional The length of the returned string if `num` is positive, the length of the two?s complement if `num` is negative.
Returns:	bin : str Binary representation of `num` or two?s complement of `num`.

num : int

Only an integer decimal number can be used.

width : int, optional

The length of the returned string if num is positive, the length of the two?s complement if num is negative.

Returns:

bin : str

Binary representation of num or two?s complement of num.

Notes

binary_repr is equivalent to using base_repr with base 2, but about 25x faster.

References

[R16]

(1, 2) Wikipedia, ?Two?s complement?, http://en.wikipedia.org/wiki/Two?s_complement

Examples

>>> np.binary_repr(3)
'11'
>>> np.binary_repr(-3)
'-11'
>>> np.binary_repr(3, width=4)
'0011'

The two?s complement is returned when the input number is negative and width is specified:

>>> np.binary_repr(-3, width=4)
'1101'

Links:

https://docs.scipy.org/doc/numpy-1.11.0/reference/generated/numpy.binary_repr.html

doc_NumPy

2017-01-10 18:12:57

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