ArcGIS-Python WIndow-Compare feature class fields using sets

compare_fields_with_sets.py

l1_name = []
with arcpy.da.SearchCursor(r"layer1", ("OID@", "Name")) as cursor:  
	for row in cursor:  
		l1_name.append(row[1])

l2_name = []
with arcpy.da.SearchCursor(r"layer2", ("OID@", "Name")) as cursor2:  
	for row in cursor2:  
		l2_name.append(row[1])


# find names in source not in target
l1_not_in_l2 = list(set(l1_name)-set(l2_name))


# if you want to use it result in a def query
# make an in clause
l1_not_in_l2_wrap = ["\'{}\'".format(x) for x in l1_not_in_l2]

l1_not_in_l2_in = ",".join(s_a_wrap)