Calculate Time Difference

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04-27-2016 07:31 AM
ErnestoCarreras3
Occasional Contributor


I have a python script that used to work to calculate difference in dates outputting the result in days. It worked fine since last week until we migrated to 10.4. To my understanding, this should not matter but just as en extra info.

(datetime.datetime.now() - arcpy.time.ParseDateTimeString( !DATE! )).days

The following error is returned:

Executing: CalculateField gishw.PU.MapChangeRequest Time_Diff (datetime.datetime.now() - arcpy.time.ParseDateTimeString( !DATE! )).days PYTHON_9.3 #

Start Time: Wed Apr 27 10:24:54 2016

ERROR 000539: Error running expression: (datetime.datetime.now() - arcpy.time.ParseDateTimeString( u"4/26/2016 4:10:00 PM" )).days

Traceback (most recent call last):

  File "<expression>", line 1, in <module>

NameError: name 'arcpy' is not defined

Failed to execute (CalculateField).

Failed at Wed Apr 27 10:24:54 2016 (Elapsed Time: 0.13 seconds)

Any assistance will be appreciated.

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10 Replies
DanPatterson_Retired
MVP Esteemed Contributor

you have to import arcpy, particularly if you are working in a python ide outside of arcmap

add this line to code

import arcpy

if it errors out, then the installation isn't correct

ErnestoCarreras3
Occasional Contributor

Yes, I am working on a python IDE. When executed from the IDE, it says in runs but the record is not updated in the Time_Diff field. That is why I went to the field calculator to just test the script which was working last week. This is a simple script that used to update one of the widgets in a dashboard.

# Import arcpy module
import arcpy

conn = r"C:\Users\gispu\Documents\GIS_Python_Scripts\Map_Change_Request\GISHW.sde"
arcpy.env.workspace = conn

# Local variables:
Input_MapChangeRequest = r"C:\Users\gispu\Documents\GIS_Python_Scripts\Map_Change_Request\GISHW.sde\gishw.PU.HW_FieldCollection\gishw.PU.MapChangeRequest"
MapChangeRequest_Layer = "PU.MapChangeRequest_Layer"
MapChangeRequest_Layer2 = MapChangeRequest_Layer

PU_MapChangeRequest_Layer = MapChangeRequest_Layer2

# Process: Make Feature Layer
arcpy.MakeFeatureLayer_management(Input_MapChangeRequest, MapChangeRequest_Layer)

# Process: Select Layer By Attribute
arcpy.SelectLayerByAttribute_management(MapChangeRequest_Layer, "NEW_SELECTION", "STATUS = 'Open' OR STATUS = 'Validation'")

# Start an edit session. Must provide the workspace.
edit = arcpy.da.Editor(conn)

# Edit session is started without an undo/redo stack for versioned data
edit.startEditing(True)

# Start an edit operation
edit.startOperation()

# Process: Calculate Field
arcpy.CalculateField_management(Input_MapChangeRequest, "Time_Diff", "(datetime.datetime.now() - arcpy.time.ParseDateTimeString( !DATE! )).days", "PYTHON_9.3", "")

# Stop the edit operation.
edit.stopOperation()

# Stop the edit session and save the changes
edit.stopEditing(True)

EDIT: 2016-04-28

The above script is good and works as expected.

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AdrianWelsh
MVP Notable Contributor

Ernesto,

Did you import arcpy into your Field Calculator? I see it in your stand alone script but I am wondering about the field calculator portion. Or is the exact script above the same you used in Field Calculator?

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ErnestoCarreras3
Occasional Contributor

No, the arcpy module was not imported when using the Field Calculator. If needed, can you provide an example of how to? BTW, I found it odd that it is needed since I already tested it before within the Field Calculator wand I don't recall adding the import module part.

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AdrianWelsh
MVP Notable Contributor

Ernesto,

Just add it to the top of the code block scripting area like you would in a standalone script. Here are some examples:

Calculate Field—Data Management toolbox | ArcGIS for Desktop

import arcpy

arcpy.env.workspace = "C:/data"

arcpy.AddField_management("vegtable.dbf", "VEG_TYP2", "TEXT", "", "", "20")

arcpy.CalculateField_management("vegtable.dbf", "VEG_TYP2", '!VEG_TYPE!.split(" ")[-1]', "PYTHON_9.3")

EDIT: I have not tested this. I am just kind of going off of the documentation.

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DanPatterson_Retired
MVP Esteemed Contributor

If you are using the field calculator and not the calculate field tool, there should be no need to import arcpy.  Also I see that sde is involved... this is about the 12 post this week with issues of calculating stuff in files that reside or are destined to sde.  I wonder if it is just the week, or some bigger issue going on with the explanations in the documentation.  Try working local, store remotely in the short term.

ErnestoCarreras3
Occasional Contributor

Thanks for the info... I was just checking out your blog

I will try to run the same process with a File GDB in order to isolate the issue. If it does work, I will report it here for the record.

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DanPatterson_Retired
MVP Esteemed Contributor

where is datetime imported?  I don't see it anywhere it may not have even completed that line and flagged an error on the arcpy instead

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ErnestoCarreras3
Occasional Contributor

Issue solved. The script was working but for some reason the field storing the time difference got renamed with an underscore at the end. After removing it, the script is working as expected. The datetime module was not required since it is included as part of the python functions within the Field Calculator GUI.

I really appreciate your assistance Dan.

Good day.

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