Improved error message for failed stof in NumericColumnModule

torch_modules/src/NumericColumnModule.cpp

@@ -80,8 +80,9 @@ void NumericColumnModuleImpl::addToContext(std::vector<std::vector<long>> & cont
       if (index >= 0)
       {
         auto value = config.getAsFeature(column, index).get();
-        try {res = std::stof(value);}
-        catch (std::exception &) {res = defaultValue;}
+        try {res = value == "_" ? defaultValue : std::stof(value);}
+        catch (std::exception & e)
+          {util::myThrow(fmt::format("{} for '{}'", e.what(), value));}
       }
 
       contextElement.emplace_back(0);