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?

  • logging_strict@programming.dev
    2·
    14 hours ago

    a use case – feature flags

    Mix and match to plan your day

    will i be going home today?

    >>> OUTRAGED_BY_NEWS = 0b00000001
>>> GET_A_COFFEE = 0b00000010
>>> GO_FOR_A_HIKE = 0b00000100
>>> GO_FOR_A_RUN = 0b00001000
>>> GO_HOME = 0b00010000 
>>> various_flags_ored_together = GET_A_COFFEE | GO_FOR_A_RUN | GO_HOME
>>> various_flags_ored_together & GO_HOME == GO_HOME
True
>>> various_flags_ored_together & GO_FOR_A_HIKE == GO_FOR_A_HIKE
False
>>> various_flags_ored_together = GET_A_COFFEE | GO_FOR_A_RUN | GO_HOME
>>> bin(various_flags_ored_together)
'0b11010'
>>> various_flags_ored_together & OUTRAGED_BY_NEWS == OUTRAGED_BY_NEWS
>>> False
>>> bin(OUTRAGED_BY_NEWS)
>>> '0b1'
>>> various_flags_ored_together >> OUTRAGED_BY_NEWS
>>> bin(various_flags_ored_together)
'0b1101'

    Guess haven’t gone for a hike today…maybe tomorrow

    right shift removes bit at flag position. Which, in this case, happens to correspond to the right most bit.

    use case – file access permissions

    For those looking to check file access permissions there is the stat module

    >>> import stat
>>> from pathlib import Path
>>> path_f = Path.home().joinpath(".bashrc")
>>> stat.S_IRUSR
256
>>> path_f.stat().st_mode
33188
>>> is_owner_read = path_f.stat().st_mode & stat.S_IRUSR == stat.S_IRUSR
>>> is_owner_read
True
>>> path_f = Path("/etc/fstab")
>>> is_other_write = path_f.stat().st_mode & stat.S_IWOTH == stat.S_IWOTH
>>> is_other_write
False

    Assumes ~/.bashrc exists, if not choose a different file you are owner and have read access to.

    path_f.stat().st_mode & stat.S_IRUSR == stat.S_IRUSR

    Looking thru the mundane file (not Linux access control list) permissions. All those flags are crammed into st_mode. In st_mode, on/off bit at 2^8 is that on?

    Sources

    read user access stat.S_IRUSR

    write others access stat.S_IWOTH

    os.stat_result

    pathlib.Path.stat