topic Re: Compare field attributes in Python Questions

Compare field attributes

CCWeedcontrol — Sun, 12 Dec 2021 03:05:13 GMT

I have a points layer and polygon layer , I need to compare field "SiteAddres" from the points layer to "SiteAddress" to the polygon layer and if it matches i need it to populate field "Verifi" with "Match" or if it doesn't match to populate "Verifi" with "No Match". Although i am not sure what would be the best way to achieve what i am trying to do because i am trying to compare address which will have upper case and lower case and spaces. I would prefer not to do a spatial join every time i need to verify and i looked into doing it with a python script but i am not sure how to do it?

I get no error but nothing the field "Verifi" doens't get populated with "Match" or "No Match"

fc1 = "Points"
fc2 = "Polygons"

cursor1 = arcpy.da.SearchCursor(fc1, ["SiteAddres", "Verifi"])
cursor2 = arcpy.da.SearchCursor(fc2, ["SiteAddres"])

for row1 in cursor1:
    for row2 in cursor2:  
        if row2[0] == row1[0]:
            for row1 in cursor1:
                row1[1] = "Match"
            else:
                row1[1] = "No Match"

I tried spatially joining the two layers and using field calculator but i am getting an invalid syntex error on line 2.

def ifBlock( SiteAddres , [SiteAddr_1 ):
 if SiteAddres = =SiteAddr_1:
  return "Match"
 else:
  return" No Match"

ifBlock( SiteAddres , SiteAddr_1 )

Thanks.

Re: Compare field attributes

AdrianWelsh — Wed, 23 Mar 2016 15:00:23 GMT

Hi,

For your bottom block of code, using an If statement, you need to put the equal signs together

if SiteAddres == SiteAddr_1:

Plus, in the def area, in the bottom block of code, it looks like you have an open bracket without a closed bracket.

And you might need to indent more in the bottom block as well (4 spaces for an indent).

Re: Compare field attributes

DanPatterson_Retired — Sun, 12 Dec 2021 03:05:16 GMT

python parser

#code block
def ifBlock( SiteAddres , SiteAddr_1 ):  
    if SiteAddres == SiteAddr_1:  
        return "Match"  
    else:  
        return "No Match"  
#expression block
ifBlock( !SiteAddres! , !SiteAddr_1! )

Re: Compare field attributes

FreddieGibson — Wed, 23 Mar 2016 15:07:23 GMT

To update the data the first cursor needs to be an update cursor and after setting the value for the field you'd want to call the updateRow method to commit it.

See the example at the bottom of the following page.

UpdateCursor—Help | ArcGIS for Desktop

Re: Compare field attributes

WesMiller — Sun, 12 Dec 2021 03:05:18 GMT

You could set up a model that does:

Spatial join
joins the spatial join with the tables
Select the addresses that are <>
You could then field calculate verified or field calculate the addresses
remove the table join

or do your spatial join in model builder and export to python and use the resulting field as an input to the following script. The script prints the oids of the non matching of both feature classes you could easily modify to get what you need

#Script to compare 2 feature classes
#Author Wes Miller


import arcpy
import numpy as np
import datetime


#Print start time and date 
dt = datetime.datetime.now()
print dt


#The Feature Class to Check
originFC = arcpy.GetParameterAsText(0)
#The feature class with updates needed for feature class above
changeFC = arcpy.GetParameterAsText(1)


origDesc = arcpy.Describe(originFC)
oidName = origDesc.oidFieldName


field_names = arcpy.GetParameterAsText(2)#Example: "Shape","TMS","OWNERNAME","TOTBDGVAL","DISTRICT","ADD1","ADD2","ADD3","MAP","BLOCK","PARCEL","CALCULATED_ACREAGE","ADDR_SITE"


originFCarr = arcpy.da.FeatureClassToNumPyArray(originFC,(field_names),null_value=-9999)
originFCarrID = arcpy.da.FeatureClassToNumPyArray(originFC,(oidName))
changeFCarr = arcpy.da.FeatureClassToNumPyArray(changeFC,(field_names),null_value=-9999)
changeFCarrID = arcpy.da.FeatureClassToNumPyArray(changeFC,(oidName))


print "Arrays Complete"
count = 0
deletesarr = np.where(np.invert(np.in1d(originFCarr,changeFCarr)))
addsarr = np.where(np.invert(np.in1d(changeFCarr,originFCarr)))
adds = []
for each in  addsarr[0]:
    adds.append(changeFCarrID[each][0])
deletes = []
for each in deletesarr[0]:
    deletes.append(originFCarrID[each][0])


#Current Outputs are printed here for testing purposes
print adds
print 
print deletes


ndt = datetime.datetime.now()
print ndt

Re: Compare field attributes

CCWeedcontrol — Sun, 12 Dec 2021 03:05:21 GMT

I changed it to the following but i get Error 000539:,

which states...

"This error code covers a number of Python errors:

Example error 1: exceptions.TypeError: cannot concatenate 'str' and 'int' objects.

The above is a Python-specific error. The calculation is attempting to add or concatenate a string and a number. "

def ifBlock( SiteAddres , SiteAddr_1 ): 
        if SiteAddres == SiteAddr_1 :
           return "Match"
        else:
           return "NoMatch"

ifBlock( SiteAddres , SiteAddr_1)

Re: Compare field attributes

CCWeedcontrol — Wed, 23 Mar 2016 15:37:19 GMT

Hi Dan.

The after making the following like you suggest it ran" ifBlock( !SiteAddres! , !SiteAddr_1! )".

but all the records returned as "No Match". I just realized that the attributes in SiteAddr_1 are all uppercase and that the SiteAddres are proper case. I had to change the following.

if SiteAddres.lower() == SiteAddr_1.lower():

Thanks!

Re: Compare field attributes

CCWeedcontrol — Sun, 12 Dec 2021 03:05:24 GMT

I have tried the following but nothing happens i get no error either.

fc1 = "Points"
fc2 = "Polygons"

cursor1 = arcpy.da.SearchCursor(fc1, ["SiteAddres", "Verifi"])
cursor2 = arcpy.da.SearchCursor(fc2, ["SiteAddres"])

# Create update cursor for feature class 
with arcpy.da.UpdateCursor(fc1, "Verifi") as cursor:
    for row1 in cursor1:
        for row2 in cursor2:  
            if row2[0] == row1[0]:
                for row1 in cursor1:
                    row1[1] = "Match"
                else:
                    row1[1] = "No Match"

                # Update the cursor with the updated list
                cursor.updateRow(row)

Re: Compare field attributes

CCWeedcontrol — Wed, 23 Mar 2016 16:28:18 GMT

I did try making a model with model builder but i did not have any success.

Re: Compare field attributes

WesMiller — Wed, 23 Mar 2016 16:51:05 GMT

Add your field or create a copy and add a field then make your model similar to the one below.

Re: Compare field attributes

FredSpataro — Sun, 12 Dec 2021 03:05:27 GMT

Hi,

Here's a quick python snippet that will:

loop the points feature class with an update cursor
select the polygon it intersects
get the first selected polygon
check if the SiteAdress fields match when both are lowercased
set the point Verifi field
update the row

Definitely a bunch of assumptions in this and no error handling but it should get you going... Arcpy doesn't let us do spatial searches yet so you have to fallback on the "selectbylocation" tool .... it's heavy handed but works.

fc1 = "points"
fc2 = "Polygons"
lyr2 = arcpy.MakeFeatureLayer_management(fc2)
with arcpy.da.UpdateCursor(fc1, ["SHAPE@", "SiteAddress", "Verifi"]) as cursor1:
     for row1 in cursor1:
          print row1
          arcpy.SelectLayerByLocation_management(lyr2, "INTERSECT", row1[0])
          with arcpy.da.SearchCursor(lyr2, ["SiteAddress"]) as cursor2:
               row2 = cursor2.next()
               print row2
               row1[2] = "Match" if row1[1].lower() == row2[0].lower() else "No"
               print row1[2]
               cursor1.updateRow(row1)

Re: Compare field attributes

CCWeedcontrol — Wed, 23 Mar 2016 17:57:44 GMT

I am a little confused on what you mean by add your field, at what point of the model do you want me to add the field into based on your mobel? Also i am confused on the "Add Join" after the spaital join. what is the output of the spatial join suppose to be joining to?

Thanks for the replay.

Re: Compare field attributes

CCWeedcontrol — Wed, 23 Mar 2016 18:31:31 GMT

I get the following.

Runtime error

Traceback (most recent call last):

File "<string>", line 5, in <module>

RuntimeError: The operation was attempted on an empty geometry.

Thanks for the reply.

Re: Compare field attributes

CCWeedcontrol — Wed, 23 Mar 2016 18:49:47 GMT

Never mind i had the wrong layer in arcmap.

The code does work but i am trying to do all of them at one time. the code only does one at a time.

I am thinking i need to do a spatial join first.

Re: Compare field attributes

FredSpataro — Wed, 23 Mar 2016 18:51:09 GMT

Hi,

Couple questions:

1. what version of ArcGIS are you running?

2. how are you running the script? Inside ArcMap/Catlog python window, IDLE, standalone, etc

3. It looks like the syntax highlighter or copy paste didn't get the correct indents for lines 6-8. I tried to edit the original post so make sure you get a clean copy or adjust your version.

4. Is your line 5 the same as mine? for row1 in cursor1: .... if so then something is wrong with the cursor. are all the names spelled correctly?

Re: Compare field attributes

FredSpataro — Wed, 23 Mar 2016 18:53:02 GMT

It should loop all the features in the point feature class. If you're in ArcMap and you have any features selected it will only execute on those selected features so make sure you unselect all features in the point layer before running the code.

Re: Compare field attributes

CCWeedcontrol — Wed, 23 Mar 2016 20:16:39 GMT

1. 10.2.2

2. In Arcmap python window

3. i did catch that indent and fixed before i ran the code.

4. row1 in cursor1:, same as you have it.

The names are spelled correctly. Although the polygon "SiteAddres" filed address are upper case for example, "2120 RANCH RD".

Where the polygons layers "SiteAddres" are proper case for example, "2120 Ranch Rd".