topic How to Calculate or use Update Cursor to concatenate fields only for values that are None in Python Questions

How to Calculate or use Update Cursor to concatenate fields only for values that are None

GeoffreyWest — Sun, 12 Dec 2021 03:55:01 GMT

I have two values, one date and one time, I would like to only calculate my new field if the value for the field is NULL. How do I do so using ArcPy? My current code reads as.

calcExpression = "!ORIGDTDATE!+\" \"+ !ORIGDTTIME!"
 arcpy.CalculateField_management(self.line_ticket_feature_class,"emergency_overdue",calcExpression,"PYTHON_9.3")
 arcpy.CalculateField_management(self.poly_ticket_feature_class,"emergency_overdue",calcExpression,"PYTHON_9.3")‍‍‍

Re: How to Calculate or use Update Cursor to concatenate fields only for values that are None

MitchHolley1 — Sun, 12 Dec 2021 03:55:04 GMT

Something like this should work.

import arcpy

date = 'date_field'
time = 'time_field'
new = 'new_field'
feature = r'path to dataset'

with arcpy.da.UpdateCursor(feature, [new, date, time]) as cursor:
    for row in cursor:
        if row[0] is None:
            row[0] = str(row[1]) + '/' + str(row[2]) # can separate the fields with anything you'd like
            cursor.updateRow(row)‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍