Can anyone suggest a simple way to calculate a 'hash code'
from an arbitrary R object?
hash(x) should return an integer or string
with the property that
if hash(x) != hash(y) then x and y are not identical
and the time to compute hash(x) should be quite short.
Any suggestions welcome
thanks
Adrian Baddeley
On Wed, 2005-08-03 at 12:05 +0800, Adrian Baddeley wrote:> Can anyone suggest a simple way to calculate a 'hash code' > from an arbitrary R object? > > hash(x) should return an integer or string > with the property that > if hash(x) != hash(y) then x and y are not identical > and the time to compute hash(x) should be quite short. > > Any suggestions welcome > thanks > Adrian BaddeleyTake a look at Dirk Eddelbuettel's digest() function in the package of the same name on CRAN. Be sure to read the details section for caveats regarding collisions. HTH, Marc Schwartz
You can compute MD5 and SHA1 digests with the 'digest' package. -roger Adrian Baddeley wrote:> Can anyone suggest a simple way to calculate a 'hash code' > from an arbitrary R object? > > hash(x) should return an integer or string > with the property that > if hash(x) != hash(y) then x and y are not identical > and the time to compute hash(x) should be quite short. > > Any suggestions welcome > thanks > Adrian Baddeley > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html >-- Roger D. Peng http://www.biostat.jhsph.edu/~rpeng/