Jython script for Knime node that adds a column with the molecular weight

knime_jython_cdk.py

import java
import org.openscience.cdk as cdk
mdlreader = cdk.io.MDLV2000Reader

iterator = inData0.iterator()

while iterator.hasNext():
    row = iterator.next()
    rowkey = row.getKey()
    cell = row.getCell(0)
    value = str(cell)
    reader = mdlreader(java.io.StringReader(value))
    chemfile = reader.read(cdk.ChemFile())
    manip = cdk.tools.manipulator.ChemFileManipulator
    molecule = manip.getAllAtomContainers(chemfile)[0]

    clone = molecule.clone()
    atommanip = cdk.tools.manipulator.AtomContainerManipulator
    atommanip.convertImplicitToExplicitHydrogens(clone)
    molwt = atommanip.getNaturalExactMass(clone)

    newDoubleCell = DoubleCell(molwt)
    newRow = AppendedColumnRow(row, [newDoubleCell])
    outContainer.addRowToTable(newRow)