Vtgyjfy

I have a table with two elements in this format:

a b
b a
b c
c b
c d
....
f g
g f

I have to analize if the second element is equal to the first element of the following row. If it's true, 1 is set in a new field. If not the marker is added by 1 +1. This is my code so far:

with arcpy.da.SearchCursor(tab_selektiert, ["field1"],) as n1_cur:

    with arcpy.da.UpdateCursor(tab_selektiert, ["field2", "markerfield"]) as n_cur:

        filler_row = next(n1_cur)

        for n_row, n1_row in izip_longest(n_cur, n1_cur, fillvalue=filler_row):

            if n1_row[0] == n_row[0]:


                n_row1 = counter

                n_cur.updateRow(n_row)

            else:

                numcounter = + 1

                n_row1 = counter

                n_cur.updateRow(n_row)



del n_cur

del n1_cur

counter = 1

numberlist = ["1", "2", "3", "4", "5", "6", "7", "8", "9", "0"]



with arcpy.da.UpdateCursor(tab_selektiert, (ufield1, ufield2)) as u_cur:

    with arcpy.da.SearchCursor(tab_selektiert, sfield1) as s_cur:

        next(s_cur)

        for sfield1, in s_cur:

            ufield1, ufield2 = next(u_cur)




        print("field 1  " + sfield1 + "---" + "  field 2   " + ufield1)

        print("field 2 + 1   " + str(int(ufield1[-1:]) + int(1)))

        print("fiel 1   " + str(sfield1[-1:]))

        print("---")



        if sfield1 == ufield1:

            ufield2 = counter

        elif sfield1[-1] in numberlist and ufield1[-1] in numberlist:

            if int(ufield1[-1:]) + int(1) == int(sfield1[-1]):

                ufield2 = counter

            elif ufield1[-1] == "9" and sfield1[-1] == "0":

                ufield2 = counter

        else:

            counter+=1

            ufield2 = counter



        u_cur.updateRow((ufield1, ufield2))

This gets me to the Point that all fields with a continuity get the marker 1. But a break in the continuity like 'd' to 'f' don't activate the else clause. This fields are just empty, also the last row and the following rows still gets the 1 as marker.

Like @PolyGeo said, list comprehensions will help. I notice, too, that you don't define counter in your code block. Without understanding what it is, I've included it as I think you meant to have it.

    field1_list = [row[0] for row in arcpy.da.SearchCursor(tab_selektiert, ["field1"])]

    field2_list = [row[0] for row in arcpy.da.SearchCursor(tab_selektiert, ["field2"])]



    #Assuming here that counter must initialize at 1. If if should initialize at 0,

    # just change it.

    counter = 1 

    index = 0



    with arcpy.da.UpdateCursor(tab_selektiert, ["markerfield"]) as updater:

        for row in updater:

            #The value of index should never exceed len-2, since len is always

            # 1 more than the highest index value, and your function will only

            # check up to the next-to-last item in the list (the last item has

            # nothing to compare to

            if index<=len(field1_list)-2:

                n0 = field1_list[index] #The field1 value for current index

                n1 = field2_list[index] #The field2 value for the current index

                n2 = field1_list[index+1] #The field1 value for the next index

                n3 = field2_list[index+1] #The field2 value for the next index



                if n1==n2 or n3==n0 or n0==n2:

                    #EDIT: Index only increases if none of the numbers

                    # match. The markerfield is always updated with

                    # counter. 

                else:

                    #This is the condition where counter is increased

                    counter+=1



                updater.updaterRow([counter])

                index+=1



            else:

                #If you've reached the last item, update the last row with counter,

                # then break out of the loop

                updater.updateRow([counter])

                break

It's worth noting that you said counter= +1, but in python the way to do what you're trying to do is as I have it: counter+=1. I hope this helps!

Iterate your table and assign your value and the oid to variables. Create a set of OIDs with values equal to the next value by comparing the last oid to the current. Iterate one more time and update the field by checking OIDs.

oids = set ()



#perform check

with arcpy.da.SearchCursor(tab_selektiert, ["field1", "field2", "OID@"]) as curs:

    for fld1, fld2, oid in curs:

        try: lastVal

        except NameError:

            lastVal = fld2

            lastOid = oid

            continue

        if fld1 == lastVal:

            oids.add (lastOid)

        lastVal = fld2

        lastOid = oid





#update

counter = 0

with arcpy.da.UpdateCursor(tab_selektiert, ["OID@", "markerfield"]) as curs:

    for oid, mark in curs:

        if not oid in oids:

            counter += 1

        row = (oid, counter)

        curs.updateRow (row)

This is another way you can do it:

import arcpy

fc = r'C:Default.gdbadress1'

field_to_read = 'Textfield'

field_to_update = 'Integerfield'



all_letters = ''.join([i[0] for i in arcpy.da.SearchCursor(fc,field_to_read)]).replace(' ','') #Create one long string, 'abbabccbcd'

cursor = arcpy.da.UpdateCursor(fc,field_to_update)

count = 1

for pair,row in zip(zip(all_letters[1::2],all_letters[2::2]),cursor): #Iterate over pairs of letters (last letter, first letter) -> (b,b), (a,b), (c,c) etc. and the cursor

    if len(set(pair))==1: #If the letters are the same, length of set will be 1

        row[0] = count

        cursor.updateRow(row)

    else:

        count+=1

del cursor