[GIS] Summing two columns in ArcGIS Desktop, one of them has Null values

arcgis-desktopfield-calculator

I need to sum values of 2 columns in field calculator and populate a new column with the result, one of the values always in Null. I already had found a useful answer In here, but it doesn't help with the last couple of columns, that contain a date in DD.MM.YYYY (string) format- geoprocessing report shows successful operation, but the new column stays empty. Is there a small tweak i could use for the code, to make it work?

def stack(Y, Y_1):
itemList = [Y, Y_1]
myList = [Y for Y in itemList if (Y != None)]
return sum(myList)

Field value= stack( !Y!, !Y_1!)

Data table

Best Answer

Based on your comments, it sounds like sum is not quite the right name for the field. You want to coalesce two fields.

Field value = !Y! or !Y_1!

This post on StackOverflow can give you more background on coalesce.

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