Reading least significant bits in Python

I am having to parse the Facility and Severity of syslog messages in Python. These values come with each message as a single integer. The severity of the event is 0-7, specified in the 3 least significant bits in the integer. What is the easiest/fastest way to evaluate these 3 bits from the number?

开发者_Go百科

The code I have right now just does a 3 bit right shift, than multiplies that number times 8, and subtracts the result from the original.

FAC = (int(PRI) >> 3)
SEV = PRI - (FAC * 8)

There must be a less convoluted way to do this- rather than wiping out the bits, and subtracting.

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SEV = PRI & 7
FAC = PRI >> 3

Like that.

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Just apply a bit mask:

sev = int(pri) & 0x07

(0x07 is 00000111)

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Try the following

result = FAC & 0x7

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The normal way to extract the least significant bits would be to do a bitwise AND with the appropriate mask (7 in this case)