Adding dynamic text from count of features in layer using arcpy.mapping

Question

I am new to writing scripts, and I am trying to make a map series using arcpy.mapping and Data Driven Pages. I would like to put some text on the map that updates for each map in the series depending on a new definition query for my dataset of sites. So, I set up my map series based on the district numbers the sites are in (districts 1 - 32). So, the pageNum should also equal the district, and I thought I could pass the pageNum into a SQL query and get a new count of sites for each district and then insert that as dynamic text using text.replace.

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I was able to get my code to work, so I am replacing the erroneous code with the functioning one.

import arcpy, string, os

mxdPath = "CURRENT"
outPath = r"D:\Geoprocessing\CDMAPS\PDFs\MapPage\\"
SitesConDist = r"D:\Geoprocessing\CDMAPS\MXDs_and_Geodatabase\CDMaps.mdb\Sites\SitesCD"
outputMXD = "D:\Geoprocessing\CDMAPS\MXDs_and_Geodatabase\SeriesMXDs\\"

try:
    mxd = arcpy.mapping.MapDocument(mxdPath)
    ddp = mxd.dataDrivenPages
    df = arcpy.mapping.ListDataFrames(mxd, "Cong*")[0]    
    for pageNum in range(1, mxd.dataDrivenPages.pageCount +1):
        
        
        mxd.dataDrivenPages.currentPageID = pageNum
        distNo = str(mxd.dataDrivenPages.currentPageID)
        arcpy.MakeFeatureLayer_management("SitesConDist","siteLyr","[congress_dist_no] = "+ distNo,"#","")
        
        defCorp = "[COnly] = 'X'"
        defCoop = "[COOP] = 'X' AND [COnly] IS NULL"
        defNSIP = "[NSIP_Full_or_Partial] = 'X'"
        defDisc = "[agency_use_cd] NOT IN ( 'A' , 'L' , 'M' )"

        arcpy.SelectLayerByAttribute_management("siteLyr","NEW_SELECTION",defCorp )
        corpscount = str(arcpy.GetCount_management("siteLyr"))
        arcpy.AddMessage(corpscount + " corps gages in district " + str(pageNum))
        print corpscount + " corps gages in district " + str(pageNum)
        
        arcpy.SelectLayerByAttribute_management("siteLyr", "NEW_SELECTION",defCoop)
        coopcount = str(arcpy.GetCount_management("siteLyr"))
        arcpy.AddMessage(coopcount + " coop gages in district " + str(pageNum))
        print coopcount + " coop gages in district " + str(pageNum)
        
        arcpy.SelectLayerByAttribute_management("siteLyr", "NEW_SELECTION",defNSIP)
        nsipcount = str(arcpy.GetCount_management("siteLyr"))
        arcpy.AddMessage(nsipcount + " nsip gages in district " + str(pageNum))
        print nsipcount + " nsip gages in district " + str(pageNum)
        
        arcpy.SelectLayerByAttribute_management("siteLyr", "NEW_SELECTION",defDisc)
        disccount = str(arcpy.GetCount_management("siteLyr"))
        arcpy.AddMessage(disccount + " discontinued gages in district " + str(pageNum))
        print disccount + " discontinued gages in district " + str(pageNum)
        
        for elm in arcpy.mapping.ListLayoutElements(mxd, "TEXT_ELEMENT"):
                if elm.name == "CorpCount":
                    elm.text = "(" + corpscount + ")"
                    print "Corp line in legend has been replaced"
                if elm.name == "CoopCount":
                    elm.text = "(" + coopcount + ")"
                    print "Coop line in legend has been replaced"
                if elm.name == "NSIPCount":
                    elm.text = "(" + nsipcount + ")"
                    print "NSIP line in legend has been replaced"
                if elm.name == "DiscCount":
                    elm.text = "(" + disccount + ")"
                    print "Discontinued line in legend has been replaced"
        arcpy.RefreshActiveView()

        Pdf = outPath + "distNo" + str(pageNum) + ".pdf"
        arcpy.mapping.ExportToPDF(mxd, Pdf)
        mxd.saveACopy(outputMXD)
        #os.startfile(Pdf) -> this line can be used to preview each map as it is created
        arcpy.AddMessage("Created PDF {0} of {1}".format(str(mxd.dataDrivenPages.currentPageID), str(mxd.dataDrivenPages.pageCount)))
        print "Created PDF {0} of {1}".format(str(mxd.dataDrivenPages.currentPageID), str(mxd.dataDrivenPages.pageCount))
    del mxd, df

except Exception, e:
    import traceback
    map(arcpy.AddError, traceback.format_exc().split("\n"))
    arcpy.AddError(str(e))

Answer 1

On the following line:

for lyr in arcpy.mapping.ListLayers(mxd, "", df)[0]:

Try removing the [0] at the end. With this you're looking for lyr inside a single layer object. By taking out the [0] you should be able to loop over and search by name like you want