The difference between the original "reset the rightmost '1' bit", and your interpretation: "reset the rightmost bit" is the "'1'".
The rightmost bit that is set is reset. So 0x10 -> 0, and 0x1010 -> 0x1000.
If you want to extract the least significant set bit from a number 'x' you can use (x&-x):
My interpretation of Bryan's (mis?)interpretation (heh) was that since in the numbers 2 and 10 (as in his examples), the least significant bit was already 0, performing an operation that set it to 0 should result in the number unchanged. As his tests show, this is not the case. This is because the operation works only if the least significant bit actually NEEDS to be unset. To zero the least significant bit unconditionally, we can use:
x &= ~1
-- Brian Beck Adventurer of the First Order -- http://mail.python.org/mailman/listinfo/python-list
