On Feb 23, 2009, at 4:48 PM, Greg Landrum wrote:
Somehow it has happened that the RDKit does not have a function to
generate the chemical formula for a molecule, so one would need to
write it from scratch. Here's a simple (and relatively untested) way
of doing this:
Ideally it would generate the Hill formula,
ks = cnts.keys()
ks.sort()
res=''
for k in ks:
res+=k
if cnts[k]>1:
res+=str(cnts[k])
would be more like:
ks = cnts.keys()
# Alphabetize everything
ks.sort()
# Put into Hill order (C then H then everything else)
if "C" in cnts:
ks.remove("C")
ks.insert(0, "C")
if "H" in cnts:
ks.remove("H")
ks.insert(1, "H")
...
There are other solutions which are more efficient for large N, but
there's only about 100 elements in the world, and only a handful in
most compounds.
Andrew
[email protected]
