Python int to binary string?

Question

Are there any canned Python methods to convert an Integer (or Long) into a binary string in Python?

There are a myriad of dec2bin() functions out on Google... But I

Answer 1

As a reference:

def toBinary(n):
    return ''.join(str(1 & int(n) >> i) for i in range(64)[::-1])

This function can convert a positive integer as large as 18446744073709551615, represented as string '1111111111111111111111111111111111111111111111111111111111111111'.

It can be modified to serve a much larger integer, though it may not be as handy as "{0:b}".format() or bin().

Answer 2

Using numpy pack/unpackbits, they are your best friends.

Examples
--------
>>> a = np.array([[2], [7], [23]], dtype=np.uint8)
>>> a
array([[ 2],
       [ 7],
       [23]], dtype=uint8)
>>> b = np.unpackbits(a, axis=1)
>>> b
array([[0, 0, 0, 0, 0, 0, 1, 0],
       [0, 0, 0, 0, 0, 1, 1, 1],
       [0, 0, 0, 1, 0, 1, 1, 1]], dtype=uint8)

Answer 3

Python's string format method can take a format spec.

>>> "{0:b}".format(37)
'100101'

Format spec docs for Python 2

Format spec docs for Python 3

Answer 4

Somewhat similar solution

def to_bin(dec):
    flag = True
    bin_str = ''
    while flag:
        remainder = dec % 2
        quotient = dec / 2
        if quotient == 0:
            flag = False
        bin_str += str(remainder)
        dec = quotient
    bin_str = bin_str[::-1] # reverse the string
    return bin_str 

Answer 5

here is simple solution using the divmod() fucntion which returns the reminder and the result of a division without the fraction.

def dectobin(number):
    bin = ''
    while (number >= 1):
        number, rem = divmod(number, 2)
        bin = bin + str(rem)
    return bin

Answer 6

you can do like that :

bin(10)[2:]

or :

f = str(bin(10))
c = []
c.append("".join(map(int, f[2:])))
print c