Using update cursor to populate a field based on a Date field in ArcPy

Question

I'm trying to populate a field (Season, "TEXT") in my attribute table with a season code based on a sampling date (FIXDATE, "DATE"). For example sample collected between 01/01/2016 and 01/03/2016 would get season code "SPRING". I'm new to arcpy and search cursors. Here is my code so far.

import arcpy
from datetime import datetime
caribou = "C:/Python/Test_data.gdb/test_data"
fields = ['FIXDATE', 'Season']
with arcpy.da.UpdateCursor(caribou, fields) as cursor:
 for row in cursor:
 if (row[0] >= datetime.strptime("01/01/2016", "%d/%m/%y") and row[0] <= datetime.strptime("01/03/2016", "%d/%m/%y")):
 row[1] = "SPRING"
 elif (row[0] >= datetime.strptime("02/03/2016", "%d/%m/%y")and row[0] <= datetime.strptime("01/06/2016", "%d/%m/%y")):
 row[1] = "SUMMER"
 elif (row[0] >= datetime.strptime("02/06/2016", "%d/%m/%y") and row[0] <= datetime.strptime("01/10/2016", "%d/%m/%y")):
 row[1] = "FALL"
 elif (row[0] >= datetime.strptime("02/10/2016", "%d/%m/%y")):
 row[1] = "WINTER"
 # Update the cursor with the updated list
 cursor.updateRow(row)

• Evan: What's happening so far with your result? Not sure if this was a copy/paste error, but you need to indent your cursor loop (for row in cursor... inside the with statement.
• Midavalo: What happens when you run this? Are there errors or just a result you're not expecting/wanting?
• rkite: Thanks. Yes I have been getting this error message: File "C:\Python27\ArcGIS10.1\lib_strptime.py", line 328, in _strptime data_string[found.end():]) ValueError: unconverted data remains: 16

Answer 1

You need to convert row[0] to the same format as your datetime.strptime("02/06/2016", "%d/%m/%y"), and also your %y needs to be %Y for the 4 digit year. I have added an extra line myDate = datetime.strptime(datetime.strftime(row[0], "%d/%m/%Y"), "%d/%m/%Y") to convert the row[0] and then use that in each if/elif for comparison.

import arcpy
from datetime import datetime
caribou = "C:/Python/Test_data.gdb/test_data"
fields = ['FIXDATE', 'Season']
with arcpy.da.UpdateCursor(caribou, fields) as cursor:
 for row in cursor:
 myDate = datetime.strptime(datetime.strftime(row[0], "%d/%m/%Y"), "%d/%m/%Y")
 if (myDate >= datetime.strptime("01/01/2016", "%d/%m/%Y") and myDate <= datetime.strptime("01/03/2016", "%d/%m/%Y")):
 row[1] = "SPRING"
 elif (myDate >= datetime.strptime("02/03/2016", "%d/%m/%Y")and myDate <= datetime.strptime("01/06/2016", "%d/%m/%Y")):
 row[1] = "SUMMER"
 elif (myDate >= datetime.strptime("02/06/2016", "%d/%m/%Y") and myDate <= datetime.strptime("01/10/2016", "%d/%m/%Y")):
 row[1] = "FALL"
 elif (myDate >= datetime.strptime("02/10/2016", "%d/%m/%Y")):
 row[1] = "WINTER"
 # Update the cursor with the updated list
 cursor.updateRow(row)