Checking value of field based on conditional if statement using ArcPy cursors

Question

I'm using ArcGIS desktop 10.6 and executing an arcpy script.

I'm creating a script that checks an input shapefiles field values against a set of rules. To do so I've created 2 lists with unique values of 2 fields within my input shapefile.

These are the UniqueDispTypeValues list and RelUnqID list.

I also have created a list of allowable values to check against.

This is the DispTypeValues list.

I created an if else statement to check a basic rule (If only RTF value exists the Rel_Unq_ID must be 0), however I want to check the current value of the field after the if statement(kind of validating a field value, or passing a rule in my case) instead of just the print statement.

Here is a screenshot of the attribute table:

Here is the code:

# Importing necessary modules
import arcpy, os

arcpy.env.overwriteOutput = True

# Setting path to mxd and Data Frame
mxd = arcpy.mapping.MapDocument(r"CURRENT")
df = arcpy.mapping.ListDataFrames(mxd)[0]

# Assign the OneSTOP shapefile to a variable
shp = r"P:\JOBS\2020\20-1095\Outgoing_Information\OneSTOP\Disposition.shp"

#Create the unique list of allowable Disposition Types
def DTV(CHK_TABLE , Disp_Type):
    with arcpy.da.SearchCursor(CHK_TABLE, [Disp_Type]) as cursor:
        return sorted({row[0] for row in cursor})
    
DispTypeValues = DTV(r'Q:\GIS\OneSTOP\OneSTOP2.gdb\Checklist' , 'Disp_Type')

print (DispTypeValues)

#Create the unique list of Disposition Types in the input shapefile
def UDTV(shp , Disp_Type):
    with arcpy.da.SearchCursor(shp, [Disp_Type]) as cursor:
        return sorted({row[0] for row in cursor})
    
UniqueDispTypeValues = UDTV(shp , 'Disp_Type')

print (UniqueDispTypeValues)

#Create the unique list of Rel_Unq_ID in the input shapefile
def RUID(shp , Rel_Unq_ID):
    with arcpy.da.SearchCursor(shp, [Rel_Unq_ID]) as cursor:
        return sorted({row[0] for row in cursor})
    
RelUnqID = UDTV(shp , 'Rel_Unq_ID')

print (RelUnqID)

length = len(UniqueDispTypeValues)

print (length)

for value in UniqueDispTypeValues:
    if value == 'RTF' and length == 1:
        print "Rel_Unq_ID must be 0"
    else:
        print "Rel_Unq_ID must be non zero"

Answer 1

For starters, you don't need to declare a function for each attempt to get unique values. See below for an example of how to create a single re-usable function. This makes your code easier to maintain and read.

Second - you can use that same function to pull the object ids of rows that meet whatever criteria you determine is a fail. In the example, I've just pulled rows with a Rel_Unq_Id < 0. The 'criteria' parameter in my GetUniqueValues function is optional - if you don't specify it, you'll get values from all records in the shapefile. If you do specify it, you'll only get values from rows that match the criteria.

# Importing necessary modules
import arcpy, os

arcpy.env.overwriteOutput = True

def GetUniqueValues(shp , field, criteria = None):
    with arcpy.da.SearchCursor(shp, [field], criteria) as cursor:
        return sorted({row[0] for row in cursor})

# Setting path to mxd and Data Frame
mxd = arcpy.mapping.MapDocument(r"CURRENT")
df = arcpy.mapping.ListDataFrames(mxd)[0]

# Assign the OneSTOP shapefile to a variable
shp = r"P:\JOBS\2020\20-1095\Outgoing_Information\OneSTOP\Disposition.shp"

#Create the unique list of allowable Disposition Types   
DispTypeValues = GetUniqueValues(r'Q:\GIS\OneSTOP\OneSTOP2.gdb\Checklist' , 'Disp_Type')

print (DispTypeValues)

#Create the unique list of Disposition Types in the input shapefile   
UniqueDispTypeValues = GetUniqueValues(shp , 'Disp_Type')

print (UniqueDispTypeValues)

#Create the unique list of Rel_Unq_ID in the input shapefile
RelUnqID = GetUniqueValues(shp , 'Rel_Unq_ID')

print (RelUnqID)

length = len(UniqueDispTypeValues)

print (length)

for value in RelUnqID:
    if value < 0:
        ids = GetUniqueValues(shp, 'OBJECTID', 'Rel_Unq_ID = ' + str(value))
        print ("Rows with Rel_Unq_ID of " + str(value))
        print (ids)