如何在鼠尾草中将十进制转换为固定长度的二进制

Question

I want to convert a decimal to binary. I am expecting binary number in the fixed length. example if fixed length is 5, 3 converted as 00011. I need to work these in sage

Answer 1

You can write a small function to do that, like:

def binary(n, length=5):
    """
    Return a binary string of specified length for this integer

    The binary string is padded with initial zeros if needed.
    The default length of 5 can be overriden.

    EXAMPLES::

        sage: binary(3)
        '00011'
        sage: binary(3, length=7)
        '0000011'
        sage: binary(3, length=1)
        ---------------------------------------------------------------------------
        ValueError                                Traceback (most recent call last)
        ...
        ValueError: Writing 3 in binary requires more than 1 bits
    """
    if length < n.nbits():
        raise ValueError('Writing {} in binary requires more than {} bits'.format(n,length))
    return '0' * (length-n.nbits()) + n.binary()

Then use it as follows:

sage: binary(3)
'00011'
sage: binary(3, length=7)
'0000011'

It will raise a ValueError if the length you ask is too short.