ProcessSampleData can end up with data sets out of alignment

[tonyroberts]

In process_sample_data.py around line 108:

                self._timestamps.append(current_timestamp)
                self._flow_rates.append(current_flow_rate)
                self._tidal_volumes.append(current_tidal_volume)
                if current_pressure != math.inf:
                    self.pressures.append(current_pressure)

These lists should all be the same size, but if for whatever reason there is no pressure data for one line then the pressures list will end up being out of alignment with the others.

My suggested fix is to add None where there is no data, but I don't know enough about the rest of the code to know if that will have any knock on effects or not.

                self._timestamps.append(current_timestamp)
                self._flow_rates.append(current_flow_rate)
                self._tidal_volumes.append(current_tidal_volume)
                self._pressures.append(current_pressure if current_pressure != math.inf else None)

[mmroden]

great idea, would love to see in a PR

[fpdotmonkey]

You could also do something like this

            if (PRESSURE_MARKER in datum):
                current_pressure = float(splitDatum[3]
                                         .replace(PRESSURE_MARKER, "")
                                         .strip("\n")) / 10
            else:
                current_pressure = None

            if ([current_flow_rate, current_tidal_volume, current_pressure]
                    != previous_data):
                self._timestamps.append(current_timestamp)
                self._flow_rates.append(current_flow_rate)
                self._tidal_volumes.append(current_tidal_volume)
                self.pressures.append(current_pressure)

However, I'll offer that this was written to narrowly support the data that's in Tests/TestData/, where this issue doesn't occur. If there were to be new test data, you'd probably want a larger refactor rather than small improvements on this code.