topic Re: Never ending While Cant figure out my error? in Python Questions

Never ending While Cant figure out my error?

AliciaMein — Tue, 11 Mar 2014 16:20:20 GMT

for row in wtlndRow:                  if row.WtlndUnitID is None:             totalArea = 0             wtlndUnitID += 1             adjWtlnd = arcpy.MakeFeatureLayer_management(wtlnd4Units, "in_memory\\adjWtlnd")             arcpy.SelectLayerByLocation_management(adjWtlnd,"SHARE_A_LINE_SEGMENT_WITH",row.shape, "", "NEW_SELECTION")             numPolys = 1             count = 0              while numPolys != count:                 numPolys = arcpy.GetCount_management(adjWtlnd)                 arcpy.SelectLayerByLocation_management(adjWtlnd,"SHARE_A_LINE_SEGMENT_WITH", wtlnd4Units,"",  "ADD_TO_SELECTION")                 count = arcpy.GetCount_management(adjWtlnd)

Cant figure out why this wont evaluate to true.
Thanks!
Alicia

Re: Never ending While Cant figure out my error?

JoshuaChisholm — Sun, 12 Dec 2021 01:54:16 GMT

Hello Alicia,

I don't think you can use arcpy.MakeFeatureLayer_management like that. I think you have to refer to the feature layer using "in_memory\\adjWtlnd".
Try changing:

adjWtlnd = arcpy.MakeFeatureLayer_management(wtlnd4Units, "in_memory\\adjWtlnd")

To:

arcpy.MakeFeatureLayer_management(wtlnd4Units, "in_memory\\adjWtlnd")
adjWtlnd = "in_memory\\adjWtlnd"

Re: Never ending While Cant figure out my error?

AliciaMein — Sun, 12 Dec 2021 01:54:19 GMT

#Create "in_memory" feture class for processing
#
    arcpy.MakeFeatureLayer_management("wtlnd4Anlys", "in_memory\\wtlnd4Units")
    wtlnd4Units = "in_memory\\wtlnd4Anlys"

#Loop through wetlands and select the adjacent polys populate WtlndUnitID and UnitArea
#
    wtlndRow = arcpy.SearchCursor("wtlnd4Anlys")
    wtlndUnitID = 0
    for row in wtlndRow:
        
        if row.WtlndUnitID is None:
            totalArea = 0
            wtlndUnitID += 1
            arcpy.MakeFeatureLayer_management("wtlnd4Anlys", "in_memory\\adjWtlnd")
            adjWtlnd = "in_memory\\adjWtlnd"
            arcpy.SelectLayerByLocation_management(adjWtlnd,"SHARE_A_LINE_SEGMENT_WITH",row.shape, "", "NEW_SELECTION")
            numPolys = 1
            count = 0

            while numPolys != count:
                numPolys = arcpy.GetCount_management(adjWtlnd)
                arcpy.SelectLayerByLocation_management(adjWtlnd,"SHARE_A_LINE_SEGMENT_WITH", wtlnd4Units,"",  "ADD_TO_SELECTION")
                count = arcpy.GetCount_management(adjWtlnd)

I made changes, but now I receive an error at :

  arcpy.SelectLayerByLocation_management(adjWtlnd,"SHARE_A_LINE_SEGMENT_WITH", wtlnd4Units,"",  "ADD_TO_SELECTION")

ERROR 000732: Selecting Features: Dataset in_memory\wtlnd4Anlys does not exist or is not supported

It seems it will take the in_memory: adjWtlnd but wont accept the second in_memory. But Im not really sure.
Thanks for your help!
Alicia

Re: Never ending While Cant figure out my error?

ClintDow — Sun, 12 Dec 2021 01:54:22 GMT

That problem seems to be related to the first couple lines:

    arcpy.MakeFeatureLayer_management("wtlnd4Anlys", "in_memory\\wtlnd4Units")
    wtlnd4Units = "in_memory\\wtlnd4Anlys"

You output to "in_memory\\wtlnd4Units", but the wtlnd4Units string is "in_memory\\wtlnd4Anlys"
From what I can tell from your script those should be the same strings.

Re: Never ending While Cant figure out my error?

DouglasSands — Sun, 12 Dec 2021 01:54:24 GMT

Hello Alicia,

I don't think you can use arcpy.MakeFeatureLayer_management like that. I think you have to refer to the feature layer using "in_memory\\adjWtlnd".
Try changing:
adjWtlnd = arcpy.MakeFeatureLayer_management(wtlnd4Units, "in_memory\\adjWtlnd")
To:
arcpy.MakeFeatureLayer_management(wtlnd4Units, "in_memory\\adjWtlnd")
adjWtlnd = "in_memory\\adjWtlnd"

Just to clarify, the code as written initially

adjWtlnd = arcpy.MakeFeatureLayer_management(wtlnd4Units, "in_memory\\adjWtlnd")

should be fine, unless in memory layers work differently for some reason. This is how I always create feature layers, as it saves a line of code and you don't have to worry so much about typos. MakeFeatureLayer_management returns a string, which is the name of the created layer.

Re: Never ending While Cant figure out my error?

DouglasSands — Sun, 12 Dec 2021 01:54:27 GMT

for row in wtlndRow:
        
        if row.WtlndUnitID is None:
            totalArea = 0
            wtlndUnitID += 1
            adjWtlnd = arcpy.MakeFeatureLayer_management(wtlnd4Units, "in_memory\\adjWtlnd")
            arcpy.SelectLayerByLocation_management(adjWtlnd,"SHARE_A_LINE_SEGMENT_WITH",row.shape, "", "NEW_SELECTION")
            numPolys = 1
            count = 0

            while numPolys != count:
                numPolys = arcpy.GetCount_management(adjWtlnd)
                arcpy.SelectLayerByLocation_management(adjWtlnd,"SHARE_A_LINE_SEGMENT_WITH", wtlnd4Units,"",  "ADD_TO_SELECTION")
                count = arcpy.GetCount_management(adjWtlnd)

Cant figure out why this wont evaluate to true.
Thanks!
Alicia

Have you tried printing the values of numPolys and count to the screen? Could provide a hint...

Re: Never ending While Cant figure out my error?

AliciaMein — Sun, 12 Dec 2021 01:54:29 GMT

That problem seems to be related to the first couple lines:
    arcpy.MakeFeatureLayer_management("wtlnd4Anlys", "in_memory\\wtlnd4Units")
    wtlnd4Units = "in_memory\\wtlnd4Anlys"
You output to "in_memory\\wtlnd4Units", but the wtlnd4Units string is "in_memory\\wtlnd4Anlys"
From what I can tell from your script those should be the same strings.

Thanks let me try that as well!!!
I need a break from this code for a little while obviously.
I did not see it!
Thanks
Alicia

Re: Never ending While Cant figure out my error?

AliciaMein — Wed, 26 Mar 2014 17:11:10 GMT

Can anyone break this line down?

int(arcpy.GetCount_management(tempLayer).getOutput(0))

I saw this used in a for loop, and wonder if I should go this direction, because I can not make this loop work as it is.

Re: Never ending While Cant figure out my error?

ClintDow — Wed, 26 Mar 2014 17:43:32 GMT

That line returns the number of rows in a feature class and ensures it is an integer. The getOutput() is because GetCount_management returns a results object, so this gets the value rather than the object.

Re: Never ending While Cant figure out my error?

AliciaMein — Wed, 26 Mar 2014 18:21:13 GMT

I am just now incorporating this. I am all but positive this is the answer I was needing. Thanks!

I did test and this does solve the endless loop, but I do not want to say that this code is perfect yet. I am still working on the iterative selection which is not working as expected.

Thanks!!!