Search Cursor not obeying selection rules

Question

Hello, I have a script that uses a search cursor to go to a selected feature in a table called SplicePoints_test, that is selected based on it intersecting with some fibercable. After that I use the selected feature and extract the last 2 digits of the string of the selected entry in the SplicePoints_test layer. However when I use the searchcursor to extract the closure_name row, it iterates through all splice points and only appends the last one in the table. I used a break statement to get it to stop iterating, but it only goes to the first one instead, any ideas on how I might get the search cursor to only acknowledge the selected feature?

with arcpy.da.SearchCursor("Fibercable_Test", ['comments']) as cursor:
    # Iterate through the rows

for row in cursor:
            arcpy.management.SelectLayerByLocation(
            in_layer="SplicePoints_test",
            overlap_type="INTERSECT",
            select_features="Fibercable_test",
            search_distance=None,
            selection_type="NEW_SELECTION",
            invert_spatial_relationship="NOT_INVERT"
            )
            #iterate through the selected splice point, and split the last digit
            with arcpy.da.SearchCursor("SplicePoints_Select", ['closure_name']) as cursor:
                for row in cursor:
                    last_2 = row[0].split('_')[3]
                    arcpy.AddMessage(last_2)

# add split string to the end of the comments field    
            expr = "'{}{}{}'".format(entry, '.', last_2)
            arcpy.management.CalculateField(
            in_table="Fibercable_test",
            field="comments",
            expression=expr,
            expression_type="PYTHON3",
            code_block="",
            field_type="TEXT",
            enforce_domains="NO_ENFORCE_DOMAINS"
            )

Hayden Welch · Answer

In my experience it can sometimes be significantly faster than SelectByLocation or a full iterative filter. Here's a quick test using my cursor module that wraps all that in a nice interface:

The top call is getting a count of features that intersect the indexed polygon using the Cursor spatial_filter and the last one is using a SelectByLocation.

Clubdebambos · Answer

Beautiful! I always forget about the (not so) new spatial_filter. Very neat.

Hayden Welch · Answer

You can actually accomplish this whole thing using cursors:

from arcpy.da import SearchCursor, UpdateCursor

with UpdateCursor("Fibercable_Test", ['OID@', 'SHAPE@', 'comments']) as cur:
    for oid, cable, comment in cur:
        int_closures: list[str] = [
            closure_name.split('_')[-1]
            for closure_name, in
            SearchCursor(
                "SplicePoints_test", ['closure_name'], 
                spatial_filter=cable)
        ]
        if not int_closures:
            continue

print(f"Found {len(int_closures)} closures for cable {oid}")

# Your original code only stores the last intersecting splice
        # You may want to join them?
        all_closures = f"({','.join(int_closures)})"
        cur.updateRow((cable, f"{comment}.{int_closures[-1]}"))

Edit: typo in that script, I forgot to add oid to the updateRow call. It should be the first element of the tuple.

Cursors accept geometry objects as spatial filters! Which means you can skip using layer selections and just keep it compact.

Edit: Made some minor changes after re-reading your script and realizing that you just drop all but the last intersecting splice closure.