how to update field with name of FC for list of FCs ?

GabrielBacca-Cortes · ‎02-10-2015

Hi Everybody -

I am trying to fill in the attribute in a newly created field 'Particle', with the name of the FC, which will be changing for a list of FCs. I've tried using 'CalculateField', with which I get the error: 'NameError: name 'xy_1' is not defined', where 'xy_1' is the name of the FC going through the loop.

I've tried using 'UpdateCursor' and I get the error: " 'list' object has no attribute 'setValue' ".

This is the code I've written so far:

fieldName1 = "Particle"

fieldType1 = "TEXT"

fieldlength = 20

wildcard = ""

fctype = ""

try:

fcList = arcpy.ListFeatureClasses(wildcard, fctype)

# print fcList2

for fc in fcList:

print fc

arcpy.AddField_management(fc,fieldName1,fieldType1,"","",fieldlength,"","NULLABLE")

[with:]

desc = arcpy.Describe(fc)

val = desc.name

print val

arcpy.CalculateField_management(fc, fieldName1, val, "PYTHON_9.3")

[OR:]

## curs = arcpy.da.UpdateCursor(fc,fieldName1)

## for row in curs:

## desc = arcpy.Describe(fc)

## val = desc.name

## print val

## row.setValue(fieldName1,val)

## curs.updateRow(row)

## del curs, row

XanderBakker · ‎02-11-2015

You're welcome...

BlakeTerhune · ‎02-11-2015

In the line where you open the update cursor, why do you have extra parenthesis around fld_name?

with arcpy.da.UpdateCursor(fc, (fld_name)) as curs:

TomSellsted · ‎02-11-2015

Blake,

It must be a tuple. The extra parenthesis make it a tuple.

Regards,

Tom

BlakeTerhune · ‎02-11-2015

But the Esri documentation for the Update cursor says:

For a single field, you can use a string instead of a list of strings.

I'm not trying to be a nit-pick know-it-all, I'm just trying to understand.

TomSellsted · ‎02-11-2015

Blake,

You are correct, the docs do say you can use a string for a single field. In this case just a coding preference. If you had more fields, the tuple would already be in place.

Regards,

Tom

BlakeTerhune · ‎02-11-2015

Ah, yes, I follow now. However, I think you have to put an extra comma after the variable inside the parenthesis to make it a true tuple.

fld_name = "Particle"
print fld_name
print (fld_name)
print (fld_name,)

produces:

Particle
Particle
('Particle',)

GabrielBacca-Cortes · ‎02-11-2015

Blake - yes, it is meant for a list of fields, which in my case is only one. As it is use in this link ArcGIS Help 10.1 , scroll down to the updateRow function.

Gabriel