topic Re: AddMessage question in Python Questions

AddMessage question

AmyKlug — Fri, 24 May 2013 20:03:42 GMT

How would you do this using AddMessage instead of print and in a script tool? My code has a parameter and where_clause in the search cursor so the user inputs a name and I would like a message listing field values.

ESRI expample:

import arcpy # Open a searchcursor #  Input: C:/Data/Counties.shp #  Fields: NAME; STATE_NAME; POP2000 #  Sort fields: STATE_NAME A; POP2000 D rows = arcpy.SearchCursor("c:/data/counties.shp",                           fields="NAME; STATE_NAME; POP2000",                           sort_fields="STATE_NAME A; POP2000 D")  # Iterate through the rows in the cursor and print out the # state name, county and population of each. for row in rows:     print("State: {0}, County: {1}, Population: {2}".format(         row.getValue("STATE_NAME"),         row.getValue("NAME"),         row.getValue("POP2000")))

Re: AddMessage question

T__WayneWhitley — Sat, 11 Dec 2021 14:01:04 GMT

...for 'print' substitute 'arcpy.AddMessage' with the message enclosed in parenthesis. Just make sure your indention is correct.

As in:

arcpy.AddMessage("State: {0}, County: {1}, Population: {2}".format(row.getValue("STATE_NAME"), row.getValue("NAME"), row.getValue("POP2000")))

I think that will work...test it out.

Re: AddMessage question

AmyKlug — Fri, 24 May 2013 22:13:08 GMT

I did try that but it will run the code but will ignore the "AddMessage"

Re: AddMessage question

T__WayneWhitley — Sat, 11 Dec 2021 14:01:07 GMT

Any error messages? ...you have to run this as a script tool via ArcGIS's toolbox to 'port' it to it's geoprocessor interface. You don't have to define any parameters, but must display it's dialog window to see the returned messages - of course if erroring out before you get to the messages you've attempted to add, then you won't see them.

If the message itself is a problem, then try formatting the text before you add it to the AddMessage parameter...debatably easier to read the code that way anyway.

...as in:

theMessage = "State: {0}, County: {1}, Population: {2}".format(row.getValue("STATE_NAME"), row.getValue("NAME"), row.getValue("POP2000"))
arcpy.AddMessage(theMessage)

Again, make sure you don't have an indention error earlier in the code block. If you're still having problems, include more complete details what you are doing and any feedback messages.

Re: AddMessage question

AmyKlug — Sat, 11 Dec 2021 14:01:10 GMT

I took your advice and got it to work like this:

import arcpy
LID = arcpy.GetParameterAsText(0)
rows = arcpy.SearchCursor("C:/Python/Python.gdb/Counties", "LINE_ID = 'LID'")
for row in rows:
    row.getValue(rows)
theMessage = "State: {0}, Name: {1} , Population: {2}".format(
            row.getValue("STATE_NAME"),
            row.getValue("NAME"),
            row.getValue("POP2000"))
arcpy.AddMessage(theMessage)
del rows, LID

I needed to define "theMessage" without indentation and add row.getValue(rows) instead under "for row in rows".

THANK YOU!!!!!!!!!!

Re: AddMessage question

AmyKlug — Sat, 11 Dec 2021 14:01:12 GMT

I took your advice and got it to work like this:

import arcpy
LID = arcpy.GetParameterAsText(0)
rows = arcpy.SearchCursor("C:/Python/Python.gdb/Counties", "LINE_ID = 'LID'")
for row in rows:
    row.getValue(rows)
theMessage = "State: {0}, Name: {1} , Population: {2}".format(
            row.getValue("STATE_NAME"),
            row.getValue("NAME"),
            row.getValue("POP2000"))
arcpy.AddMessage(theMessage)
del rows, LID

I needed to define "theMessage" without indentation and add row.getValue(rows) instead under "for row in rows".

THANK YOU!!!!!!!!!!

OK this worked while I was in my other MXD but now since I have opened a new mxd it is telling me the same error that the row.getvalue(State_Name) "row" is not defined. arrrrggggg!

It wont work again in any mxd.

EDIT: I think the reason it was working is because to make sure the fields would print i ran the print code first (see my first post) and that is where it was getting it's "row" definition

Re: AddMessage question

T__WayneWhitley — Sat, 11 Dec 2021 14:01:15 GMT

Amy, that code makes no sense - should fail at:
row.getValue(rows)

...because 'rows' is your cursor object, not a field name -- try this, your code corrected from above - you must have the correct county feature class to run this on:

import arcpy
LID = arcpy.GetParameterAsText(0)
rows = arcpy.SearchCursor("C:/Python/Python.gdb/Counties", "LINE_ID = 'LID'")

for row in rows:
     theMessage = "State: {0}, Name: {1} , Population: {2}".format(row.getValue("STATE_NAME"), row.getValue("NAME"), row.getValue("POP2000"))
     
        arcpy.AddMessage(theMessage)

del rows, LID

Careful with indention!

Enjoy,
Wayne

EDIT: Or, if this helps you, the backslash is to Python a 'line continuation' character, meaning what you see in italic text should be a single line of code, expressed below perhaps easier-to-read:

for row in rows:
     theMessage = "State: {0}, Name: {1}, Population: {2}".\
                     format(row.getValue("STATE_NAME"), \
                            row.getValue("NAME"), \
                            row.getValue("POP2000"))        
     arcpy.AddMessage(theMessage)

Re: AddMessage question

AmyKlug — Sat, 11 Dec 2021 14:01:18 GMT

Whenever I use arcpy.AddMessage indented under "for row in rows" it just gets ignored and no message appears even though the code runs without error

import arcpy
LID = arcpy.GetParameterAsText(0)
rows = arcpy.SearchCursor("C:/Python/Python.gdb/Counties", "LINE_ID = 'LID'")
for row in rows:
       theMessage = "State: {0}, Name: {1} , Population: {2}".format(row.getValue("STATE_NAME"),
row.getValue("NAME"),row.getValue("POP2000"))
       arcpy.AddMessage(theMessage)
del rows, LID

Edit: my code looks different when posted. might be having formatting issues

The "print" version works fine in the python window so I am assuming my feature class is ok.

Re: AddMessage question

T__WayneWhitley — Tue, 28 May 2013 17:46:39 GMT

I edited my response above because I was having trouble formatting my message...

Do you have a script tool? Are you running the code from the toolbox? Try editing the script tool py you are using, pasting in the portion from above...again, if there's a problem, I need to know what the error messages are.

Of course if not running from ArcToolbox, then of course you won't see the messages.

Hope that helps.
Wayne

Re: AddMessage question

AmyKlug — Tue, 28 May 2013 17:57:00 GMT

I edited my response above because I was having trouble formatting my message...

Do you have a script tool? Are you running the code from the toolbox? Try editing the script tool py you are using, pasting in the portion from above...again, if there's a problem, I need to know what the error messages are.

Of course if not running from ArcToolbox, then of course you won't see the messages.

Hope that helps.
Wayne

I tried that and same thing and pasted that code in (yes, running and editing from toolbox with a script tool). No error or message 😞

Re: AddMessage question

T__WayneWhitley — Tue, 28 May 2013 18:00:49 GMT

Are you showing the dialog box window messages? There's a checkbox you can check on or off to show the messages...that's where they print to so I suspect you're simply not displaying it. ...also do you know where to look at the Results panel? You may optionally look at messages for each run and see any you have printed (along with error messages, if any, etc).

Re: AddMessage question

AmyKlug — Tue, 28 May 2013 18:08:51 GMT

I've been viewing message in the results window..................when the message shows up. When I indent arcpy.AddMessage under "for row in rows" it just lets me know that the tool completed. No message

Re: AddMessage question

T__WayneWhitley — Tue, 28 May 2013 18:16:39 GMT

Do you know you just said 'arcpy.GetMessage'... that is totally different!

Re: AddMessage question

AmyKlug — Tue, 28 May 2013 18:17:41 GMT

Sorry...type o. fixed

Re: AddMessage question

T__WayneWhitley — Tue, 28 May 2013 18:22:24 GMT

Have you set up the tool to accept your input parameter for the query you are trying to apply?

...ahh, I see a problem with your query:
"LINE_ID = 'LID'"

LID is supposed to be a variable, not the text 'LID', understand?

Re: AddMessage question

T__WayneWhitley — Tue, 28 May 2013 19:15:51 GMT

This is kind of an important detail, easy to overlook, so I'm posting once more to clarify (hopefully).

Since this was a file gdb (as hard-coded in the script) and using GetParameterAsText for the var LID to 'filter' the search cursor, this query should work:

rows = arcpy.SearchCursor("C:/Python/Python.gdb/Counties", "LINE_ID = '" + LID + "'")

There's more than 1 way to enter a query, but basically from the webhelp topic, Specifying a Query in Python (http://resources.arcgis.com/en/help/main/10.1/index.html#//002z0000001r000000), a better recommended approach is something like:

qry = """%s = '%s'""" % (arcpy.AddFieldDelimiters(fc, "LINE_ID"), LID)
rows = arcpy.SearchCursor("C:/Python/Python.gdb/Counties", qry)

Hope that at least sums up better this rather lengthy thread --- for those still unsure what was happening, the incorrect query ("LINE_ID = 'LID'") was returning an empty set hence no messages...nothing to print.

Enjoy,
Wayne

Re: AddMessage question

AmyKlug — Tue, 28 May 2013 20:00:02 GMT

Worked like a charm. Muchas Gracias. Looks like I need to learn more about queries!