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Python @programming.dev milon @lemm.ee 2d ago

Why can't I use the '|' bitwise operator in this statement?

if coin == 25 | 10 | 5:

If I replace the '|' with 'or' the code runs just fine. I'm not sure why I can't use '|' in the same statement.

Doing the following doesn't work either:

if coin == 25 | coin == 10 | coin == 5:

I know bitwise operators can only be used with integers, but other then that is there another difference from logical operators?

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29 comments

| is not equivalent to "or". In bitwise operations the integer is converted into bits and the operation is done on a per-bit level. See: https://www.geeksforgeeks.org/python-bitwise-operators/

Eg. 1 | 2 is 3 where as 1 or 3 is 1
- Exactly. OP is looking for a Boolean logical operator “or” and not the bitwise operator “|”.
- I did come across that link but didn't quite understand it. If looking only at 25 | 10, does the code not run as expected because 25 is 5 digits long and 10 is 4 digits long? Is that what's meant by "two equivalent length bit designs"?
  
  Also, I can't tell if 10 | 4 = 7 or 10 | 4 = 14.
  
  0d10 = 0b00001010 0d04 = 0b00000100 1010 | 0100 ------ 1110 0b00001110 = 0d14 0d25 = 0b00011001 0d10 = 0b00001010 11001 | 01010 ------- 11011 0b00011011 = 0d27
  
  If an int is only x bytes long, but y bytes are needed for an action, it's just padded with 0's to the left. So 0b110 = 0b0110 = 0b00000110. Usually you will use either 8, 16, 32 or 64 digits/bits (char, short, int and long respectively, and 1, 2, 4 and 8 bytes long, 1 byte = 8 bits. So you'll usually align it with bytes.) However, for calculating like this removing trailing zeroes can make it more tidy, and sometimes 4 or 2 bits are used too. And bools technically only use 1 bit.
  
  Thank you. Not sure why in the link the arithmetic in green results in 7.

29 comments