topic Update date field in Python Questions

Update date field

LauraBusolo2 — Mon, 29 Jan 2018 23:00:12 GMT

I'm pretty new to python and I have a table in a geodatabase that contains info on data sources, names, targets and a date field. I have a script that copies features based on a user's input, e.g. if ft_ID ==1. then copy features. I want to update the date field based on the affected/copied features row that the "copy features" was executed, and I don't know how to. (e/g. If I copy feature with ID as "1", update the corresponding date field for today/whatever day I copy that field). I just know I may need to use an update cursor.

I was playing around with the update cursor, but only got it to work to update current date for all features. This is how it looks like so far.

LYR_UPDATE_TABLE = r".\...gdb\Layer_Update"

#FIELD_NAMES = ['a', 'b', 'c', 'LastUpdate']

fld = 'LastUpdate'

btch_num = raw_input ("Please enter ID: ")

with arcpy.da.UpdateCursor (LYR_UPDATE_TABLE, fld) as dt_cursor:

for row in dt_cursor:

# btch_id was defined earlier as the user's input to choose the features to cpy from the table

if batch_id == int(btch_num):

#Update the LastUpdate field with the date of the copy features-update

"""row [6] = (...)"""

dt_cursor.updateRow([datetime.date.today()])

print ('date Update Success!')

Re: Update date field based on row edited

JoshuaBixby — Tue, 30 Jan 2018 02:51:02 GMT

Are you getting an error, is so, what? Provide the whole traceback.

Re: Update date field based on row edited

LauraBusolo2 — Tue, 30 Jan 2018 03:30:47 GMT

The error was:

ValueError: need more than 1 value to unpack

Re: Update date field based on row edited

RandyBurton — Sun, 12 Dec 2021 02:18:03 GMT

Usually the error will also indicate a line number and the module where the script had problems. The complete error message block would help.

In the meantime, you might try something like:

LYR_UPDATE_TABLE = r"C:\Path\to\file.gdb\Layer_Update"

fld = 'LastUpdate'

btch_num = raw_input("Please enter a valid Batch ID: ") #assuming you are outside arcmap

where_clause = "batch_id = '{}'".format(btch_num) # where will limit to matching rows

with arcpy.da.UpdateCursor (LYR_UPDATE_TABLE, fld, where_clause) as dt_cursor:
    for row in dt_cursor:
        row[0] = datetime.datetime.strftime(datetime.date.today(),"%Y-%m-%d")
        dt_cursor.updateRow(row)‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

I am assuming you are using a file geodatabase, and working outside ArcMap. You can limit the rows in the cursor with a where clause. Line 11 shows how you can format your date. Hope this helps.

Edit:

For the where clause, if the field type is numeric, omit the single quotes around the field value:

where_clause = "batch_id = {}".format(btch_num) # where will limit to matching rows
‍

Re: Update date field based on row edited

LauraBusolo2 — Tue, 30 Jan 2018 07:13:01 GMT

The error is related to the line with the row.

See below:

File "testscript.py", line 16, in <module>
batch_id, source_path, source_name, target_path, target_name, method, last_update= row #This is line 16, which reflects variables for the field names in the table
ValueError: need more than 1 value to unpack

Re: Update date field based on row edited

DanPatterson_Retired — Sun, 12 Dec 2021 02:18:06 GMT

from this line

batch_id, source_path, source_name, target_path, target_name, method, last_update= row

7 values were expected... row .... provided 1. which I suspect was empty.

As a check, put...

print(row) immediately before that line and see if it prints out 7 values, if not, then there is something wrong with the input data. Certainly there is something wrong with the code logic since that case should be checked for and accounted for in the script

row = [1, 2, 3, 4, 5, 6, 7]

a, b, c, d, e, f, g = row

print(row)
[1, 2, 3, 4, 5, 6, 7]

print(a, b, c, d, e, f, g)
1 2 3 4 5 6 7

row = [1, 2, 3]

# ---- how to check
if len(row) == 7:
    print('good')
else:
    print('not enough values{}'.format(row))
    
not enough values[1, 2, 3]‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: Update date field based on row edited

XanderBakker — Tue, 30 Jan 2018 12:54:16 GMT

As a side note... if you enable editor tracking ArcGIS will maintain a date field and editor field to store the last edit: Enable Editor Tracking—Data Management toolbox | ArcGIS Desktop

Re: Update date field based on row edited

JoshuaBixby — Tue, 30 Jan 2018 15:00:35 GMT

You created the update cursor with a single field, i.e., fld. In Line 16, you are trying to unpack a single item tuple into 7 different variables, hance the error that you need more than 1 value to unpack. Instead of passing fld to the cursor, pass FIELD_NAMES.

Re: Update date field based on row edited

RandyBurton — Tue, 30 Jan 2018 17:15:18 GMT

In the field list (commented out) you have "BatchID" and in your code you are testing with "if batch_id == ..." If these are field names, they are not the same field. Did you mean them to be the same?