[Python] How do bitwise operations work in Python?

I have been learning about Bitwise operations today and I learned that Not (~) inverses all bits, e.g.:

01010
to
10101


which means ~10 should be -5 but instead I have seen that it is -11 (per the python command line) which is

01010
to
11011


only two of the bits have been inverted. Can anybody explain why it isn't 10101?

EDIT: After looking on my calculator I understand it a little better, But my own code for determining binary and ints is still being confused. Entering in (in byte mode) 11110101 gives me -11 but the same entered in my code gives -117:

def binaryToInt(biNum, bUnsigned = False):
iNum = 0
bSign = int(biNum[0]) if not (bUnsigned or biNum[-1] == "u") else 0
biNum = biNum[(1 if not (bUnsigned or biNum[-1] == "u") else 0)len(biNum) if biNum[-1] != "u" else -1)]
for i in xrange(len(biNum)):
iNum += int(biNum) * 2**(len(biNum) - 1 - i)
return (iNum if not bSign else -iNum)

def intToBinary(iNum, bUnsigned = False):
bSign = "1" if iNum < 0 else "0"
iLoopNum = int((iNum ** 2) ** 0.5) #make positive!
biNum = ""
while iLoopNum:
biNum += str(iLoopNum%2)
iLoopNum /= 2
return bSign + biNum[::-1] if not bUnsigned else biNum[::-1] + "u"


can one of you explain that?

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