I suggest taking a look at http://desktop.arcgis.com/en/arcmap/10.3/tools/coverage-toolbox/select.htm or ArcGIS Help 10.1 if pre-10.1, you'll need to do a quick web search for the help
So, I can get you part way there. I haven't figured out the correct syntax for the reselect and nselect yet. The error I'm getting is
Enter a logical expression. (Enter a blank line when finished)
>: RESELECT FID LT 16
** Item "FID" not found **
>: NSELECT
NSELECT cannot be the first selection expression.
Character string expected.
** An expression must start with RES, ASEL, NSEL or ITEMS.
** NO VALID EXPRESSION ENTERED **
*** UNABLE TO PERFORM ACTION ***
Bailing out of EVALUATE
Failed to execute (Reselect).
Failed at Wed Sep 14 19:03:52 2016 (Elapsed Time: 0.37 seconds)
I have also tried it with RES and NSEL.
Here is the code that I have so far. Again, it gives some good info up to the infoExpress and the Reselect_arc part
import arcpy
inCover = r"C:\Workspace\test\bl01"
arcpy.env.workspace = inCover
featureType = 'point'
recCountIn = int(arcpy.GetCount_management(featureType).getOutput(0))
print("Number of {0} records in {1}: {2}".format(featureType, inCover, recCountIn))
featureClassList = arcpy.ListFeatureClasses()
fieldList = arcpy.ListFields(inCover, "", featureType)
fieldString = [str(x.name) for x in fieldList]
print(fieldString)
tempCover = r"C:\Workspace\test\cl01testIn"
try:
arcpy.Copy_management(inCover, tempCover)
print("\nCopy worked")
except:
print("\nCopy didnt work, may already exist")
tempCoverOut = r"C:\Workspace\test\cl01Out"
fidfilter= 'fid < 16'
print("\nReselect {0} from {1} then nselect for the other {2} and save to new coverage".format(fidfilter, recCountIn, (recCountIn - int(fidfilter[-3:]))))
infoExpress = ["RESELECT FID LT 16",
"NSELECT"]
print("\n my test infoExpress: {0}\n but doesn't work".format(infoExpress))
"""
infoExpress = ["RESELECT stream_name CN 'AQUEDUCT'",
"NSELECT",
"RESELECT stream_order > 3",
"ASELECT length > 10000"]
"""
arcpy.Reselect_arc(tempCover, tempCoverOut, infoExpress, featureType, "", "")
Unless you have to do it all in the source coverage, I would use a copy (just in case) and then do a Reselect to a new coverage. If you run it more than once, you will have to so clean up, of course. And that assumes you get it to work, which as mentioned, right now the infoExpress is not quite right yet. Also, change to your input/workstation, etc.
As mentioned in the other thread, you might be better off moving to a FGDB and featureclasses now, but I was always a coverage fan, and know there may be reasons....so, work with what you need to. have fun!