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Parse Invalid Characters Arcpy

RusselKlueg

Hi all,

I'm back at it again. I've written a script to Iterate through an MXD and export all features within 50 miles of my state to a feature class. There are over 550 FCs to process and it keeps failing due to invalid characters. Does arcpy offer a way to parse out invalid characters when naming a conversion output?

Below is the code i'm referencing

import arcpy
import glob
import os
files = glob.glob(r'C:\Users\JOC-001\Documents\GIS\HSIP\IL_Infrastructure2015\*')
for f in files:
    os.remove(f)

mxd = arcpy.mapping.MapDocument(r'C:\Users\JOC-001\Documents\GIS\HSIP\Infrastructure\HSIP_Gold_2015_Infrastructure.mxd')  
  
layers = arcpy.mapping.ListLayers(mxd)  
  
for lyr in layers:  
    if lyr.isGroupLayer:
        pass
    else:
        print lyr
        arcpy.SelectLayerByLocation_management(lyr, "WITHIN_A_DISTANCE", r"C:\Users\JOC-001\Documents\ArcGIS\Default.gdb\Illinois", "50 Miles", "NEW_SELECTION")  
        arcpy.FeatureClassToFeatureClass_conversion(lyr, r'C:\Users\JOC-001\Documents\GIS\HSIP\IL_Infrastructure2015', str(lyr.name))

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Accepted answers

DarrenWiens2

Could you post the entire error message? What is an example of an invalid character? Is it always the same character that you could simply replace or ignore?

You might try Copy Features rather than Feature Class to Feature Class, as well.

All comments

MGAL

Six years later, the solution worked like a charm.

As a bit of background, I was creating individual FC's from a larger FC based on an attribute.

The MB failed due to spaces & dashes in the attribute name. As a workaround, I created a new field and calculated using the following expression.

import re
def strip_invalid(plant):
    x = re.sub('[^A-Za-z0-9]+', '', plant)
    return x

Thanks, @JoshuaBixby !!

RusselKlueg

I'm still fairly new to python and I'm not sure how that method works. I would say i know just enough to casue myself a lot of problems! Would you mind giving a quick explanation? If not i'll dive into the python help pages! I did get my code working though. I'll post it below if you want to see it.

import arcpy
import glob
import os


#glob is used to use the wildcard option for anything under this file  to allow for removal of all files
files = glob.glob(r'C:\Users\JOC-001\Documents\GIS\HSIP\IL_Infrastructure2015\*')
for f in files:
    os.remove(f)
#Defines 'mxd' as the Map Document to be referenced
mxd = arcpy.mapping.MapDocument(r'C:\Users\JOC-001\Documents\GIS\HSIP\Infrastructure\HSIP_Gold_2015_Infrastructure.mxd') 
#Defines the layers to be used as everything under Layers dataframe in the table of contents for the mxd
layers = arcpy.mapping.ListLayers(mxd) 
#Iterates over each layer in the list of 'layers'
for lyr in layers:
    #checks to see if any file is a Group layer rather than a single layer
    if lyr.isGroupLayer:
        pass
    #Once layers pass the group layer check this initiates the geoprocessing.
    else:
        lyr2 =  ''.join(ch for ch in str(lyr) if ch.isalnum())
        print lyr2
       
        arcpy.SelectLayerByLocation_management(lyr, "WITHIN_A_DISTANCE", r"C:\Users\JOC-001\Documents\ArcGIS\Default.gdb\Illinois", "50 Miles", "NEW_SELECTION") 
        arcpy.FeatureClassToFeatureClass_conversion(lyr, r'C:\Users\JOC-001\Documents\GIS\HSIP\IL_Infrastructure2015', lyr2)

GrantHerbert

arcpy.ValidateTableName does a good job of removing problematic characters as well.

ArcGIS Help 10.1

XanderBakker

That is a nice method that Joshua Bixby shows to obtain a valid file name, although in special cases it may produce problems, but I like it (clean and short code). Probably going into to much detail, but there is a slugify project at GitHub that goes more into detail (also for URLs):

python-slugify/slugify.py at master · un33k/python-slugify · GitHub

and some discussions here:

Turn a string into a valid filename in Python - Stack Overflow

python - Create (sane/safe) filename from any (unsafe) string - Stack Overflow

Validate a filename in python - Stack Overflow

JoshuaBixby

Since you didn't give a specific example, I am guessing you are running into layer names that contain Windows file system reserve characters, e.g., a colon, double quote, etc.... Feature Class to Feature Class fails because the underlying call to create the new feature class fails at the OS level.

If you are willing to limit output names to only alphanumeric ASCII characters, you could also try the sub method in the regular expression module.

re.sub('[^A-Za-z0-9]+', '', lyr.name)

RusselKlueg

I actually found a pretty nice method to handle converting a string to Alpha Numeric characters

''.join(ch for ch in str(lyr) if ch.isalnum())

as for the copy features, thats a much better idea than FC2FC.

DarrenWiens2

Could you post the entire error message? What is an example of an invalid character? Is it always the same character that you could simply replace or ignore?

You might try Copy Features rather than Feature Class to Feature Class, as well.

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