Update shapefile data source with wildcard using python

Question

I am attempting to update a layer's data source in Arcmap using python

for lyr in arcpy.mapping.ListLayers(mxd, "*", df):
    if lyr.name == "project_whl":
        lyr.replaceDataSource("F:\\Jobs2012\\05665\\EPASS\\", "SHAPEFILE_WORKSPACE","1205992_whl")

This WORKS!

HOWEVER I would like to use a wildcard instead of explicitly stating the dataset_name

Example below:

for lyr in arcpy.mapping.ListLayers(mxd, "*", df):
        if lyr.name == "project_whl":
            lyr.replaceDataSource("F:\\Jobs2012\\05665\\EPASS\\", "SHAPEFILE_WORKSPACE","*whl")

Yet does not work, I have tried *, ?, %, _, & none of these work...

Just get the following error message

<type 'exceptions.ValueError'>: Layer: Unexpected error

Your thoughts, ideas?

Answer 1

Yeah - I wouldn't expect any sort of wildcard specification to work due to the risk of returning multiple possible candidate shapefile datasources. I think you'll have to add a function to get the shapefile name via the Python OS namespace. Something like this should work:

def getFileName(dir):
 import os
 for root, dirs, files in os.walk(dir):
  for f in files:
   if "shp" in f:
    return f.replace('.shp','')

# And then you're loop will look like this:
for lyr in arcpy.mapping.ListLayers(mxd, "*", df):
 if lyr.name == "project_whl":
  myFile = getFileName("SHAPEFILE_WORKSPACE")
  lyr.replaceDataSource("F:\\Jobs2012\\05665\\EPASS\\", "SHAPEFILE_WORKSPACE",myFile)

Note that this method will return the first shapefile encountered in SHAPEFILE_WORKSPACE

Answer 2

In general, unless the documentation says something should work, don't expect it to. :)

Here's what the Layer documentation has on the dataset_name parameter:

A string that represents the name of the dataset the way it appears in the new workspace (not the name of the layer in the TOC). If dataset_name is not provided, the replaceDataSource method will attempt to replace the dataset by finding a table with a the same name as the layer's current dataset property."

So you might try leaving it blank if you want it to locate it based on the previous dataset name.

Answer 3

I ended up doing this.

Credit goes to user blah238 for suggesting using os.path.splitext

import os
import arcpy

# Function to remove ".shp" from shapefile
def delExt (shpFile):
    nPath = os.path.splitext(shpFile)
    return nPath[0]

# Update files with correct data source
os.chdir(ePassPath)
for files in os.listdir("."):
    if files.endswith("_whl.shp"):
        whlPath = files
    elif files.endswith("_aoa.shp"):
        aoaPath = files
    elif files.endswith("_ws.shp"):
        wsPath = files
    elif files.endswith("_route.shp"):
        routePath = files

#=== Loop throught layers find the one to be replaced ===

for lyr in arcpy.mapping.ListLayers(mxd, "*", df):
     if lyr.name == "project_whl":
        lyr.replaceDataSource(ePassPath, "SHAPEFILE_WORKSPACE",delExt(whlPath))
    if lyr.name == "project_aoa":
        lyr.replaceDataSource(ePassPath, "SHAPEFILE_WORKSPACE",delExt(aoaPath))
    if lyr.name == "project_ws":
        lyr.replaceDataSource(ePassPath, "SHAPEFILE_WORKSPACE",delExt(wsPath))
    if lyr.name == "project_route":
        lyr.replaceDataSource(ePassPath, "SHAPEFILE_WORKSPACE",delExt(routePath))