Dynamic segmentation with respect to a control factor

ChukwuemekaEzeiruaku

Is there a way either with python scripts or other solution to dynamically segment the following table?

Input table (not a feature class)

 

Item ID	Begin	End
1000	0	1
1001	0	5
1002	1	7
1003	4	5
1004	3	5

Each segmented section (from-to) should have all the item numbers written to a field that is within a certain range. From the input table, the final table should look like the one below:

Output table

  

Begin	End	Item ID	Item ID
0	1	1000	1001
1	3	1001	1001; 1002
3	4	1002	1001; 1002; 1004
4	5	1003	1001; 1002; 1003; 1004
5	7	1004	1002

Thanks.

blake.terhune

I tested it with your sample data, but I don't know how well it will work with more a more complex dataset. Note that the output field that lists all of the ItemID values has to have a limit, which I arbitrarily set to 255. Of course, you'll also need to change the paths and names accordingly.

def main():
    import arcpy
    import os

    # Local variables
    mygdb = r"N:\TechTemp\BlakeT\Work\TEMP.gdb"
    mytable = os.path.join(mygdb, "SegmentSequence")

    # Read input table into dictionary
    itemsdict = {}
    with arcpy.da.SearchCursor(mytable, ["ItemID", "Begin", "End"]) as s_cursor:
        for item, begin, end in s_cursor:
            itemsdict[item] = (begin, end)

    # Identify segments
    allsegments = [i[0] for i in itemsdict.values()] + [i[1] for i in itemsdict.values()]
    segments = tuple(sorted(set(allsegments)))
    del allsegments

    # Create output table
    arcpy.CreateTable_management(mygdb, "SegmentSequence_output")
    mytable_out = os.path.join(mygdb, "SegmentSequence_output")
    arcpy.AddField_management(mytable_out, "Begin", "SHORT")
    arcpy.AddField_management(mytable_out, "End", "SHORT")
    arcpy.AddField_management(mytable_out, "SegmentItems", "TEXT", field_length=255)

    # Write segment items to output table
    with arcpy.da.InsertCursor(mytable_out, ["Begin", "End", "SegmentItems"]) as i_cursor:
        for enum, seg in enumerate(segments):
            try:
                begin = seg
                end = segments[enum + 1]
            except IndexError:
                break
            seg_items = [k for k, v in itemsdict.items() if v[0] <= begin and v[1] >= end]
            row = (begin, end, str(seg_items).strip('[]'))
            i_cursor.insertRow(row)


if __name__ == '__main__':
    main()