topic Re: Using Lists with arcpy.da.UpdateCursor in Python Questions

Using Lists with arcpy.da.UpdateCursor

deleted-user-_7x2iiEJ9SpB — Fri, 13 Jul 2018 14:56:44 GMT

I am trying to use arcpy.da.UpdateCursor to find and replace old values in a field with new values. I have made it work but I will ended up with an ridiculously lard if\elif statement (notice below that I stopped after the first 2 items in the list). I would like to avoid this by iterating through both list to update the field. I have tried without any luck. Any suggestions? Code is attached.

Re: Using Lists with arcpy.da.UpdateCursor

JoshuaBixby — Sat, 11 Dec 2021 08:36:10 GMT

Assuming the mapping between the two life cycle status lists is one to one based on position in the list, the following will work:

import arcpy


fc = r'G:\pworks\assetmanagement\Local Gov Info Model\Wastewater\Inputs\Valve_Schema.gdb\SControlValve'

LifeCycleStatus1 = ["ABN", "ACT","AB","CHGORD","DEM","INA","OTH","PRP","RMV","UNK","FV", "FD"]
LifeCycleStatus2 = ["Abandoned","Active","As Built","Change Order","Demolished","Inactive","Other","Proposed","Removed","Unknown","Field Verification Required","Future Development"]


    
try:    
    cursor = arcpy.da.UpdateCursor(fc, ["LIFECYCLESTATUS"])
    for row in cursor:
        row[0] = LifeCycleStatus2[LifeCycleStatus1.index(row[0])]
        cursor.updateRow(row)
    del row 
    del cursor
except RuntimeError:
    pass
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Re: Using Lists with arcpy.da.UpdateCursor

VinceAngelo — Fri, 13 Jul 2018 15:33:29 GMT

Please remember to post code as ASCII text (formatted appropriately), so that those who would help you don't need to retype your code.

- V

Re: Using Lists with arcpy.da.UpdateCursor

deleted-user-_7x2iiEJ9SpB — Fri, 13 Jul 2018 16:26:18 GMT

Vince Angelo‌ thanks for the heads up! How do I embed the code like Joshua Bixby‌ did?

Re: Using Lists with arcpy.da.UpdateCursor

JoeBorgione — Fri, 13 Jul 2018 16:33:15 GMT

Click on the three dots above:

Click on the resulting More button and choose Syntax highlighter. Pick the language of choice, and paste your code in the window. Click Ok button at the bottom of the window...

Re: Using Lists with arcpy.da.UpdateCursor

RandyBurton — Sat, 11 Dec 2021 08:36:13 GMT

To use a dictionary instead of a list (assuming the mapping between your two lists), something like this should also work:

import arcpy

fc = r'G:\pworks\assetmanagement\Local Gov Info Model\Wastewater\Inputs\Valve_Schema.gdb\SControlValve'

LCStatus = {
    'ABN': 'Abandoned',
    'ACT': 'Active',
    'AB': 'As Built',
    'CHGORD': 'Change Order',
    'DEM': 'Demolished',
    'INA': 'Inactive',
    'OTH': 'Other',
    'PRP': 'Proposed',
    'RMV': 'Removed',
    'UNK': 'Unknown',
    'FV': 'Field Verification Required',
    'FD': 'Future Development'
    }
    
try:    
    cursor = arcpy.da.UpdateCursor(fc, ["LIFECYCLESTATUS"])
    for row in cursor:
        row[0] = LCStatus[row[0]]
        cursor.updateRow(row)
    del row 
    del cursor
except RuntimeError:
    pass‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: Using Lists with arcpy.da.UpdateCursor

deleted-user-_7x2iiEJ9SpB — Sat, 11 Dec 2021 08:36:15 GMT

Thanks for all the responses! Right after I posted this I figured it out how to do it this way. Any suggestions on adding an elif statement that will tell the user if there are any values in the field that are not in the list? Example: "ANB" instead of "ABN"

import arcpy

# My Feature Class that I want to use
fc = arcpy.GetParameterAsText(0)

# My List of old and new values
LifeCycleStatus1 = ["ABN", "ACT","AB","CHGORD","DEM","INA","OTH","PRP","RMV","UNK","FV", "FD"]
LifeCycleStatus2 = ["Abandoned","Active","As Built","Change Order","Demolished","Inactive","Other","Proposed","Removed","Unknown","Field Verification Required","Future Development"]

try:
    i=0
    for life in LifeCycleStatus1:
        cursor = arcpy.da.UpdateCursor(fc, ["LIFECYCLESTATUS"])
        for row in cursor:    
            if row[0] == LifeCycleStatus1[i]:
                row[0] = LifeCycleStatus2[i]
                cursor.updateRow(row)
        i+=1
except RuntimeError:
    pass
          ‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: Using Lists with arcpy.da.UpdateCursor

JoeBorgione — Sat, 11 Dec 2021 08:36:18 GMT

#logic:

if row[0] in listname:
  do something
elif row[0] in listname2:
  do something else
else:
  print 'Not in either list...'‍‍‍‍‍‍‍‍

Re: Using Lists with arcpy.da.UpdateCursor

RandyBurton — Sat, 11 Dec 2021 08:36:21 GMT

For the dictionary approach, a check would be something like:

    for row in cursor:
        if if row[0] not in LCStatus.keys():
            # print error message and keep original value
            print "{} not in list".format(row[0])
        else: # update value
            row[0] = LCStatus[row[0]]
            cursor.updateRow(row)‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: Using Lists with arcpy.da.UpdateCursor

RandyBurton — Fri, 13 Jul 2018 21:11:02 GMT

I notice in your second code posting, you are running multiple update cursor loops, once for each item in your list (line 12). With either the indexing solution from Joshua or the dictionary solution, only a single pass with an update cursor is needed and is more efficient.

Re: Using Lists with arcpy.da.UpdateCursor

deleted-user-_7x2iiEJ9SpB — Mon, 16 Jul 2018 11:16:04 GMT

The issue i'm running into is that I don't want it to print 100 times "not in list." I just want it to total up the number of times other values are found.

Re: Using Lists with arcpy.da.UpdateCursor

JoeBorgione — Sat, 11 Dec 2021 08:36:24 GMT

How about setting a counter variable?

counter = 0
for row in cursor:
        if if row[0] not in LCStatus.keys():
            # print error message and keep original value
            #print "{} not in list".format(row[0])
            counter +=1
        else: # update value
            row[0] = LCStatus[row[0]]
            cursor.updateRow(row)
print '{} rows not in list...'.format(counter)‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: Using Lists with arcpy.da.UpdateCursor

JoshuaBixby — Sat, 11 Dec 2021 08:36:27 GMT

It seems there may be values in the records that are not in your list. That is good information to offer up earlier in the thread since it will change the structure of the code.

Using my original code suggestion, I believe the following will work for you:

import arcpy


fc = r'G:\pworks\assetmanagement\Local Gov Info Model\Wastewater\Inputs\Valve_Schema.gdb\SControlValve'

LifeCycleStatus1 = ["ABN", "ACT","AB","CHGORD","DEM","INA","OTH","PRP","RMV","UNK","FV", "FD"]
LifeCycleStatus2 = ["Abandoned","Active","As Built","Change Order","Demolished","Inactive","Other","Proposed","Removed","Unknown","Field Verification Required","Future Development"]


    
try:    
    cursor = arcpy.da.UpdateCursor(fc, ["LIFECYCLESTATUS"])
    cnt = 0
    for row in cursor:
        if row[0] in LifeCycleStatus1:
            row[0] = LifeCycleStatus2[LifeCycleStatus1.index(row[0])]
            cursor.updateRow(row)
        else:
            cnt += 1
    del row 
    del cursor
    print("{} records didn't have Life Cycle Status values in list".format(cnt))
except RuntimeError:
    pass‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: Using Lists with arcpy.da.UpdateCursor

JoeBorgione — Mon, 16 Jul 2018 14:48:07 GMT

Joshua Bixby‌ - where does 'i' come from in line 18?

Re: Using Lists with arcpy.da.UpdateCursor

deleted-user-_7x2iiEJ9SpB — Mon, 16 Jul 2018 14:53:27 GMT

Joshua Bixby‌ it wasn't my original goal to print out the values until I realized how many we had that were missing\wrong.

Re: Using Lists with arcpy.da.UpdateCursor

JoshuaBixby — Mon, 16 Jul 2018 14:53:46 GMT

My bad, I have corrected it from "i" to "1".

Re: Using Lists with arcpy.da.UpdateCursor

RandyBurton — Sat, 11 Dec 2021 08:36:30 GMT

Something like this should give a listing with a count of the values in the LIFECYCLESTATUS field:

import arcpy

fc = r'G:\pworks\assetmanagement\Local Gov Info Model\Wastewater\Inputs\Valve_Schema.gdb\SControlValve'
field = 'LIFECYCLESTATUS'

d = {} # new dictionary

with arcpy.da.SearchCursor(fc, (field)) as rows:
    for row in rows:
        if row[0] not in d:
            d[row[0]] = 1
        else:
            d[row[0]] += 1

for k, v in d.iteritems():
    print k, v‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍