XOR on string

[snacktime]

I need to calculate the lrc of a string using an exclusive or on each
byte in the string. How would I do this in python?

Chris

 

[Peter Hansen]

I need to calculate the lrc of a string using an exclusive or on each
byte in the string. How would I do this in python?

lrc == Linear Redundancy Check? or Longitudinal? Note that
such terms are not precisely defined... generally just acronyms
people make up and stick in their user manuals for stuff.

import operator
lrc = reduce(operator.xor, [ord(c) for c in string])

Note that this returns an integer, so if you plan
to send this as a byte or compare it to a character
received, use chr(lrc) on it first.

-Peter

 

[snacktime]

lrc == Linear Redundancy Check? or Longitudinal? Note that

such terms are not precisely defined... generally just acronyms
people make up and stick in their user manuals for stuff.
Longitudinal

import operator
lrc = reduce(operator.xor, [ord(c) for c in string])

That's better than what I had, which as it turned out was working I
was just calculating the lrc on one extra digit that I should have
been.

Chris

 

[Nick Craig-Wood]

I need to calculate the lrc of a string using an exclusive or on each
byte in the string. How would I do this in python?

lrc == Linear Redundancy Check? or Longitudinal? Note that
such terms are not precisely defined... generally just acronyms
people make up and stick in their user manuals for stuff.

import operator
lrc = reduce(operator.xor, [ord(c) for c in string])

Or for the full functional programming effect...

lrc = reduce(operator.xor, map(ord, string))

which is slightly faster and shorter...

$ python2.4 -m timeit -s'import operator; string = "abcdefghij13123kj12l3k1j23lk12j3l12kj3"' \
'reduce(operator.xor, [ord(c) for c in string])'
10000 loops, best of 3: 20.3 usec per loop

$ python2.4 -m timeit -s'import operator; string = "abcdefghij13123kj12l3k1j23lk12j3l12kj3"' \
'reduce(operator.xor, map(ord, string))'
100000 loops, best of 3: 15.6 usec per loop