topic Re: UpdateCursor setValue() equivalent for da.UpdateCursor? in Python Questions

UpdateCursor setValue() equivalent for da.UpdateCursor?

KDeVogelaere — Wed, 30 Sep 2015 16:10:54 GMT

Can I rewrite the Python code below using da.UpdateCursor ? I could not find an equivalent setValue() method for da.UpdateCursor to make the changes.

i = 0
fields= ['LastName','FirstName']
values= ['Jensen','Parky']
rows = arcpy.UpdateCursor(table, where)
for row in rows:
while (i < len(fields)):
row.setValue(fields, values)
i += 1
rows.updateRow(row)
del rows, row

Are there any arcpy methods to return the index of tableName.fieldName that we can plug into row[index] when using da.UpdateCursor?

Katie

Re: UpdateCursor setValue() equivalent for da.UpdateCursor?

FreddieGibson — Sat, 11 Dec 2021 18:32:37 GMT

import arcpy


i = 0
fields = ["LastName", "FirstName"]
values = ["Jensen", "Parky"]


# Option A
with arcpy.da.UpdateCursor(table, fields, where) as cursor:
    for row in cursor:
        while (i < len(fields)):
            row = values
            i+=1
        i=0
        cursor.updateRow(row)
        
# Option B
with arcpy.da.UpdateCursor(table, fields, where) as cursor:
    for row in cursor:
        for i,value in enumerate(values):
            row = value
            cursor.updateRow(row)

Re: UpdateCursor setValue() equivalent for da.UpdateCursor?

KDeVogelaere — Wed, 30 Sep 2015 17:54:31 GMT

Thanks Freddie, what if fields[0] and fields[1] are not the first and second fields in the attribute table? Will this still work?

For example,

OBJECTID	FirstName	LastName
1	Jane	Doe

row = value // i = 0 // row[0] is OBJECTID // fields[0] is FirstName

Re: UpdateCursor setValue() equivalent for da.UpdateCursor?

WesMiller — Wed, 30 Sep 2015 17:58:25 GMT

fields[0] and fields[1] correspond to fields = ["LastName", "FirstName"]

UpdateCursor—Help | ArcGIS for Desktop

Re: UpdateCursor setValue() equivalent for da.UpdateCursor?

DarrenWiens2 — Sat, 11 Dec 2021 18:32:40 GMT

You decide which fields to include in the cursor. In doing so, you also decide the order of the fields in the cursor. Alternatively, you can include all fields by using '*', which will return all fields in the order found in the attribute table.

Consider a feature class with many fields, in any order, but you are interested in only "name", "age", and "address".

with arcpy.da.UpdateCursor("myFeatureClass",["name","age","address"]) as cursor: # you set cursor field order here
  for row in cursor: # loop through each row in the cursor
    print row[0] # name
    print row[1] # age
    print row[2] # address

vs.

with arcpy.da.UpdateCursor("myFeatureClass",["name","address","age"]) as cursor: # you set cursor field order here
 for row in cursor: # loop through each row in the cursor
   print row[0] # name
   print row[1] # address
   print row[2] # age

Re: UpdateCursor setValue() equivalent for da.UpdateCursor?

KDeVogelaere — Wed, 30 Sep 2015 18:31:53 GMT

Thanks Darren, this makes perfect sense.

One challenge I was having was updating a 'lastUpdated' column to the localtime() without passing the 'lastUpdated' field to da.UpdateCursor first. I decided to append the value of localtime() to the end of the values array and 'lastUpdated' to the end of the fields array. It's working beautifully!