How to delete selected rows using ArcPy?

Question

I want to delete all rows in a feature class but remain rows 1 to 5. In other hand I want to remain first five rows and delete others. I know that I have to use search cursor and update cursor but I couldn't use them. How can I delete the rows using ArcPy ?

• FelixIP: Select by attribute "FID" > 4 and use arcpy.Deletefeatures
• fatih_dur: Just out of curoisty, why couldn't you use cursors?
• BBG_GIS: @fatih_dur because I'm beginner in Arcpy
• kumar: import arcpy fc = r'C:\temp\test.gdb\tmp' expression = "objectid >5" with arcpy.da.UpdateCursor(fc, "OBJECTID",where_clause = expression) as cursor: for row in cursor: if row[0] > 5: cursor.deleteRow()

Answer 1

You can use an Update Cursor to delete rows based on your conditions. In this example, any rows where OBJECTID> 5 is deleted.

import arcpy
fc = r'C:\temp\test.gdb\tmp'
with arcpy.da.UpdateCursor(fc, "OBJECTID") as cursor:
 for row in cursor:
 if row[0] > 5:
 cursor.deleteRow()

Alternatively, use Select Layer By Attribute (Data Management).

import arcpy, os
fc = r'C:\temp\test.gdb\tmp'
outws = r'C:\temp\test.gdb'
# Make a layer from the feature class
arcpy.MakeFeatureLayer_management(fc, "fc_lyr")
# Use a SQL query to select OBJECTID 1 - 5
arcpy.SelectLayerByAttribute_management("fc_lyr", "", ' "OBJECTID" <= 5 ')
# Write the selected features to a new feature class
arcpy.CopyFeatures_management("fc_lyr", os.path.join(outws, "fc_out"))

• fatih_dur: +1 for keeping the original features as long as system resources allow. One question, what if the OIDs do not start from 1 and are not consecutive?
• BBG_GIS: @Aaron Thanks. Is it possible to use object id field type instead of "OBJECTID" name. because in some layers the name of object id is different.
• Vince: @faith_dur Be careful with equating "OID" and "OBJECTID"; the source format dictates behavior. The OID rowid column of shapefiles is immutable (and zero based), while an enterprise or file geodatabase OBJECTID retains value after initialization (and is usually one-based). You do have a good point that a SQL subquery with an ORDER BY and LIMIT would be necessary to identify the current first 5 rows.
• Aaron: @wetland Yes, you can use the OID@ token--simply replace "OBJECTID" with "OID@".