There appears to be a bug in the system.dataset.appendDataset() routine. I am using Ignition 7.9.10
If the second dataset contains None values, they are replaced with “0” after the appendDataset routine is run.
I tested this with the following code…
ds1 = system.dataset.toDataSet(["East", "Temp"], [[0,5],[1,2],[2,5],[5,8]])
ds2 = system.dataset.toDataSet(["West", "Temp"], [[10,5],[11,2],[12,5],[15,8]])
ds1 = system.dataset.addColumn(ds1, 1, [None]*ds1.getRowCount(), "West", int)
ds2 = system.dataset.addColumn(ds2, 0, [None]*ds2.getRowCount(), "East", int)
ds = system.dataset.appendDataset(ds1, ds2)
for dataset in [ds1, ds2, ds]:
for row in system.dataset.toPyDataSet(dataset):
print [v for v in row]
print ""
Running the above code returns the following…
[0, None, 5]
[1, None, 2]
[2, None, 5]
[5, None, 8]
[None, 10, 5]
[None, 11, 2]
[None, 12, 5]
[None, 15, 8]
[0, None, 5]
[1, None, 2]
[2, None, 5]
[5, None, 8]
[0, 10, 5]
[0, 11, 2]
[0, 12, 5]
[0, 15, 8]
If the order of the datasets in the appendDataset call is reversed, the following dataset is created…
[None, 10, 5]
[None, 11, 2]
[None, 12, 5]
[None, 15, 8]
[0, 0, 5]
[1, 0, 2]
[2, 0, 5]
[5, 0, 8]