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What I need to do:

  1. rename a field name of a table/feature class
  2. copy all values to the new field

So far I have done following code as @artwork21 suggests:

import sys
import traceback
import arcpy
from arcpy import env

## ARGUMENTS
# argv[1] = input table/feature class path
# argv[2] = input old field name
# argv[3] = input new field name  

path = sys.argv[1]
oldFieldName = sys.argv[2] 
newFieldName = sys.argv[3] 

env.overwriteOutput = True

fields = arcpy.ListFields(path)
for field in fields:
    if field.aliasName == oldFieldName:
        if not oldFieldName == newFieldName:
            fieldType = field.type
            # Add new field
            arcpy.AddField_management(path, newFieldName, fieldType)
            #Calculates the new field based on old field values
            arcpy.CalculateField_management(path, newFieldName, "!"+oldFieldName+"!", "PYTHON", "")
            # Delete the old field (if necessary)
            arcpy.DeleteField_management(path, oldFieldName)

How can I map field.type to AddField_management method's field type? And while the field is in a middle place, then field deleted from middle and added to the last. That does not looks like as if field name is renamed.

Is there any better solution that help me to do these things?

PolyGeo
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Emi
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  • Your feature layer field is not being renamed here, fieldInfo.setNewName(index, "stat"). This is why you are getting your error on line row.setValue("stat", gValue). – artwork21 Feb 20 '13 at 13:14
  • I also assume this. but why does not it renamed the field here? I can remember that, that line of code worked for me before. – Emi Feb 20 '13 at 13:27
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    setNewName (index, new_field_name), must be for only setting new field names, not renaming existing ones. – artwork21 Feb 20 '13 at 13:33
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    A FieldInfo object does not do anything to the underlying data, it is simply a representation of the field properties that can be used as an input to certain tools for creating new data, similar to a FieldMappings object. – blah238 Feb 20 '13 at 20:14
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    Is old_field a variable name or the actual name of the old field? If it's a variable name you need to use string formatting or concatenation to wrap the value of the variable with the brackets (VB parser) or exclamation points (Python parser). – blah238 Feb 21 '13 at 01:46
  • old_field is the name of the variable – Emi Feb 21 '13 at 12:48
  • can someone tell me why did i get 2 negative votes here? I did not find the problem. – Emi Feb 21 '13 at 12:50
  • Did you try my suggestions? – blah238 Feb 21 '13 at 13:03
  • @blah238: I also tried arcpy.CalculateField_management(layer, new_field, "!old_field!", "PYTHON", "").Doesn't it what you tell me to do? – Emi Feb 21 '13 at 13:05
  • No. You are using a variable name like a string literal. Python cannot read your mind. Do as I suggested and use string formatting or concatenation. – blah238 Feb 21 '13 at 13:09
  • @blah238 Thank you so much. Actually i am new in python. so at first, i did not get you. – Emi Feb 21 '13 at 13:37
  • What is the purpose of this check: field.aliasName == oldFieldName. A field alias name is allowed (really, intended) to be different from its name. Did you mean field.name? – blah238 Feb 22 '13 at 06:39
  • alias name is what we are seeing when we are looking at the table.right? – Emi Feb 22 '13 at 15:31
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    An alias in general is a "nickname" or a pseudonym. It is not necessarily equal to the actual column name in the database. – blah238 Feb 22 '13 at 16:05

5 Answers5

15

Try this using a combination of Add Field, Calculate Field, and Delete Field arcpy tools:

if fieldInfo.getFieldName(index) == "status":
    arcpy.AddField_management(layer, "stat", "TEXT", "", "", "50", "",        "NULLABLE", "NON_REQUIRED", "")                     
    arcpy.CalculateField_management(layer, "stat", "!status!", "PYTHON_9.3", "")
    arcpy.DeleteField_management(layer, "status")
artwork21
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    I want to make the two field type same. but field.Type and AddField_management method's field_type names are not same. What to do? – Emi Feb 20 '13 at 13:43
  • @Emi, I'm not understanding what you mean by "two field type same"? You want the value in "status", to be put in a new field called "stat"? – artwork21 Feb 20 '13 at 13:52
  • yes I want the value in "status", to put in the new field called "stat" – Emi Feb 20 '13 at 13:55
  • I also tried fieldInfo.addField ("status", "stat", "VISIBLE", "NONE") instead of fieldInfo.setNewName(index, "stat"). But same error happened with my code. – Emi Feb 20 '13 at 14:03
  • For rows = arcpy.UpdateCursor(inputFeatureClass) , maybe try rows = arcpy.UpdateCursor(layer) – artwork21 Feb 20 '13 at 14:10
  • I tried with layer but it does not work. the same error :( – Emi Feb 20 '13 at 14:24
  • @artwork21 what i have seen so far is, the field is created but while i tell it to do calculate field management,it says, the field is not here. – Emi Feb 20 '13 at 15:10
  • What method are you using to create the field? – artwork21 Feb 20 '13 at 15:12
  • I used this method: arcpy.AddField_management(inputFeatureClass, new_field, "TEXT") – Emi Feb 20 '13 at 15:55
  • The code snippet that I put in my answer using "layer" worked for me. Use "layer" not "inputFeatureClass" for add, calculate, and delete field arcpy tools. – artwork21 Feb 20 '13 at 16:10
  • @Emi You seem to have tried but abandoned the method offered by @artwork21? If arcpy method is a requirement his is certainly the way that I would do it. Your attempt uses "[old_field]" which is syntax that looks odd to me. – PolyGeo Feb 21 '13 at 00:18
  • Is there any way to map field.type at addField_management method's field type? – Emi Feb 22 '13 at 01:56
9

You can now rename a field using core ArcGIS Desktop GP tool - Alter Field (Data Management). This tool provides the ability to rename fields or rename field aliases for any geodatabase table or feature class.

This tool is available starting with 10.2.1.

Alex Tereshenkov
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3

To rename a field in a table or feature class I would try the procedure described here.

  1. Start ArcMap and open the Catalog window.
  2. Locate the database that contains the table you want to alter.
  3. Right-click the table and click Properties.
  4. Click the Fields tab.
  5. Click on the existing text in the Field Name column and type a new name.

I just tested this on a file geodatabase table using ArcGIS for Desktop Standard 10.1 SP1 and it worked fine.

Unfortunately, after writing this I searched the What's New in ArcGIS 10.1 PDF file and found that this functionality may have been added at that version - still it could be worth testing the latest service pack of 10.0 to see if it was back ported there too.

PolyGeo
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1

two big problems with the code:

  • if the dataType is not a FeatureLayer, the program will skip over the fieldinfo manipulations, and then try to set the value to a new/renamed field that was never created/renamed

  • The two lines:

    gValue = row.getValue("status")

    row.setValue("stat", gValue)

    have a big problem. If the earlier code worked The field "status" doesn't exist.

mhoran_psprep
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1

How can I map field.type to AddField_management method's field type?

This is done automatically, according to this post.

And while the field is in a middle place, then field deleted from middle and added to the last. That does not looks like as if field name is renamed. Is there any better solution that help me to do these things?

As I mentioned in your other question, your only other options are to drop and re-create the whole feature class/table or modify the column definition in the underlying DBMS.

I suppose you could delete all user columns and re-create them in the desired order but that's a little crazy. The script in this answer does exactly that, you could probably adapt it to your needs.

Community
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blah238
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