topic Re: Python error question in Python Questions

Python error question

DEAF_PROBERT_68 — Fri, 23 Jan 2015 00:33:13 GMT

I am a beginner and just starting to learn how to use Python I learned from Python Scripting for Map Automation.

My question to you is that whenever I get an error I see the word Traceback or errors in highlight red in my python window.

My question to you is do I need to have a pythonWin installed ? My computer at work does not have it but I use the python Window inside ArcMap.

Are there site that can I read or learn about the Traceback error ? I am sure there are bunch of question that Traceback has in it.

So what does Traceback means and what does it do ?

Thanks

Re: Python error question

XanderBakker — Fri, 23 Jan 2015 01:21:52 GMT

It helps to "trace back" the line where the error occurred.

The documentation can be found here:

28.10. traceback — Print or retrieve a stack traceback — Python 2.7.9 documentation

And you should read this help topic: Error handling with Python

Re: Python error question

DanPatterson_Retired — Fri, 23 Jan 2015 01:24:02 GMT

the python docs are here why dont you install pythonwin and/or Pyscripter the Arc* ide is pretty useless

Re: Python error question

FranciscoGirón_Gesteira — Fri, 23 Jan 2015 06:37:39 GMT

If you are just beginning there is no need to install anything. Every Python installation includes IDLE, a simple grafical interface with many basic funtionalities including debugging, colorizing, auto-indentation, etc. Not as good as Pyscripter, but is already installed. I personally don't like Pythonwin. Just a thing, if using an external IDE, remember putting an "import arcpy" line at the start of every script you write.

If you are able to install Pyscripter set up the options to read arcpy help and perform code completion with it. Just add arcpy to the special packages line under code completion in IDE options.

The Traceback shows you the line of your code where an error occurred, and which kind of error it is. It should be more than enough in the beginning, forget about try/exception and others until you are writing your own scripts.

Re: Python error question

DEAF_PROBERT_68 — Fri, 23 Jan 2015 17:47:09 GMT

the only problem is that my computer is under Government and it must be approve before I can use them. Does it have any issue ?

Re: Python error question

DanPatterson_Retired — Fri, 23 Jan 2015 17:54:13 GMT

Both are harmless although they need to make registry additions for which you may not have permissions to do. You will quickly find out if you can install either by yourself or need your Administer to do so.

Re: Python error question

DEAF_PROBERT_68 — Fri, 23 Jan 2015 19:10:41 GMT

Right now I am at work and here is the error i am having ....

>>> mxd.replaceWorkspaces("","NONE","E:\State_mosaic\Elevations.gdb","FILEGDB_WORKSPACE")

Runtime error

Traceback (most recent call last):

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

File "C:\Program Files (x86)\ArcGIS\Desktop10.1\arcpy\arcpy\utils.py", line 181, in fn_

return fn(*args, **kw)

File "C:\Program Files (x86)\ArcGIS\Desktop10.1\arcpy\arcpy\_mapping.py", line 915, in replaceWorkspaces

return convertArcObjectToPythonObject(self._arc_object.replaceWorkspaces(*gp_fixargs((old_workspace_path, old_workspace_type, new_workspace_path, new_workspace_type, validate), True)))

ValueError: MapDocObject: Unexpected error

Re: Python error question

XanderBakker — Fri, 23 Jan 2015 19:24:08 GMT

How do you set you mxd variable?

Re: Python error question

DEAF_PROBERT_68 — Fri, 23 Jan 2015 19:35:15 GMT

mxd = arcpy.mapping.MapDocument("CURRENT")

Re: Python error question

XanderBakker — Fri, 23 Jan 2015 19:42:14 GMT

That shouldn't be a problem if you run the code from the Python Window inside ArcMap.

What happens if you place an r before "E:\State_mosaic\Elevations.gdb":

mxd.replaceWorkspaces("","NONE",r"E:\State_mosaic\Elevations.gdb","FILEGDB_WORKSPACE",True)

Re: Python error question

DEAF_PROBERT_68 — Fri, 23 Jan 2015 19:48:18 GMT

I put that damn r into what you suggest and it worked ...

Is the "r" stand for reclusive , correct ?

Re: Python error question

XanderBakker — Fri, 23 Jan 2015 19:54:50 GMT

Glad it worked. The r is for "Raw String Notation":

https://docs.python.org/3.3/library/re.html#raw-string-notation (sorry 3.3 docs)https://docs.python.org/3.3/library/re.html#raw-string-notation

If you copy and paste a path in python code it will probably be invalid since you have to use double backward slashed, forwards slashes or the r in front of the string holding the path. Normally the last option is the easiest,

Re: Python error question

DEAF_PROBERT_68 — Fri, 23 Jan 2015 20:25:43 GMT

Are you saying that when I copy and paste the code into python window in ArcMap does it give you an errors ?

So that means do I have to re-type them ?

Re: Python error question

DEAF_PROBERT_68 — Fri, 23 Jan 2015 20:34:12 GMT

Earlier I mention that it worked.. That was all about the file geodatabase. Now I have one shapefile in the same mxd that did not replace to the new workspace.

>>> mxd = arcpy.mapping.MapDocument("CURRENT")

>>> path = "E:\ned10DEM\Contours"

>>> mxd.replaceWorkspaces(r"\E:\FY2011_projects\10mNED\Contours","SHAPEFILE_WORKSPACE", path + r"\","SHAPEFILE_WORKSPACE")

I still got an error here : Parsing error SyntaxError: invalid syntax (line 1)

Re: Python error question

XanderBakker — Sun, 12 Dec 2021 04:35:29 GMT

I think it should be:

mxd = arcpy.mapping.MapDocument("CURRENT")
path = r"E:\ned10DEM\Contours"
mxd.replaceWorkspaces(r"E:\FY2011_projects\10mNED\Contours","SHAPEFILE_WORKSPACE", path,"SHAPEFILE_WORKSPACE")

each time you specify a path (as string) place the r in front of it.

Re: Python error question

DEAF_PROBERT_68 — Fri, 23 Jan 2015 20:58:12 GMT

What are you using to run this code ? PyScripter ? BTW Thanks.

Re: Python error question

XanderBakker — Fri, 23 Jan 2015 21:07:08 GMT

I didn't run the code, but when I do I use PyScripter.

Re: Python error question

DEAF_PROBERT_68 — Fri, 23 Jan 2015 21:17:31 GMT

Using Python Windows within ArcMap. I think I need to try and use PyScripter. I have to ask my IT Specialist for permission to use it on my computer.

Thanks.

Re: Python error question

XanderBakker — Fri, 23 Jan 2015 21:21:58 GMT

If I'm correct you can download the ZIP which does not need an installation...

Downloads - pyscripter - An open-source Python Integrated Development Environment (IDE) - Google Project Hosting‌

zip file for registry free installation

Re: Python error question

BlakeTerhune — Fri, 23 Jan 2015 23:55:05 GMT

It installs with a different shortcut for each Python version. Do we need to make sure we are running the PyScripter for Python 2.7 so it's "compatible" with ArcGIS? I seem to remember something about this being the case.