interpret_bit_flags¶
-
astropy.nddata.bitmask.
interpret_bit_flags
(bit_flags, flip_bits=None)[source]¶ Converts input bit flags to a single integer value (bit mask) or
None
.When input is a list of flags (either a Python list of integer flags or a sting of comma- or ‘+’-separated list of flags), the returned bit mask is obtained by summing input flags.
Note
In order to flip the bits of the returned bit mask, for input of
str
type, prepend ‘~’ to the input string. ‘~’ must be prepended to the entire string and not to each bit flag! For input that is already a bit mask or a Python list of bit flags, setflip_bits
forTrue
in order to flip the bits of the returned bit mask.Parameters: bit_flags : int, str, list, None
An integer bit mask or flag,
None
, a string of comma- or ‘+’-separated list of integer bit flags, or a Python list of integer bit flags. Ifbit_flags
is astr
and if it is prepended with ‘~’, then the output bit mask will have its bits flipped (compared to simple sum of input flags). For inputbit_flags
that is already a bit mask or a Python list of bit flags, bit-flipping can be controlled throughflip_bits
parameter.flip_bits : bool, None
Indicates whether or not to flip the bits of the returned bit mask obtained from input bit flags. This parameter must be set to
None
when inputbit_flags
is eitherNone
or a Python list of flags.Returns: bitmask : int or None
Returns an integer bit mask formed from the input bit value or
None
if inputbit_flags
parameter isNone
or an empty string. If input string value was prepended with ‘~’ (orflip_bits
was set toTrue
), then returned value will have its bits flipped (inverse mask).Examples
>>> from astropy.nddata.bitmask import interpret_bit_flags >>> "{0:016b}".format(0xFFFF & interpret_bit_flags(28)) '0000000000011100' >>> "{0:016b}".format(0xFFFF & interpret_bit_flags('4,8,16')) '0000000000011100' >>> "{0:016b}".format(0xFFFF & interpret_bit_flags('~4,8,16')) '1111111111100011' >>> "{0:016b}".format(0xFFFF & interpret_bit_flags('~(4+8+16)')) '1111111111100011' >>> "{0:016b}".format(0xFFFF & interpret_bit_flags([4, 8, 16])) '0000000000011100' >>> "{0:016b}".format(0xFFFF & interpret_bit_flags([4, 8, 16], flip_bits=True)) '1111111111100011'