Add SMARTS example.

Author: cstein

simple_smarts.py

@@ -0,0 +1,28 @@
+#!/usr/bin/env python
+"""
+simple_smarts.py - simple example on how to use SMARTS patterns
+                   via the Open Babel API
+"""
+import openbabel
+
+filename = '1UAO.pdb'
+pattern = "[$(CN)][$(C=O)]"
+
+# OpenBabel utilities
+obmol = openbabel.OBMol()
+obconv = openbabel.OBConversion()
+obpat = openbabel.OBSmartsPattern()
+
+# load the molecule
+obconv.SetInFormat(filename[-3:])
+obconv.ReadFile(obmol, filename)
+
+# initialize pattern matching
+obpat.Init(pattern)
+
+# apply pattern matching to the molecule
+obpat.Match(obmol)
+
+# avoid getting lots of <openbabel.vectorvInt; proxy ... > etc.
+matches = [m for m in obpat.GetUMapList()]
+print matches