topic Re: Using Python Dictionaries to Change Feature Class Names in Python Questions

Using Python Dictionaries to Change Feature Class Names

NataliaGutierrez1 — Sat, 11 Dec 2021 10:41:03 GMT

Hello!

I recently posted a question about python dictionaries and here I am again struggling with them..

I am now trying to use them to change feature class names.

Problem:

I have a list of 77 feature classes and I need to change their names from codes to names using a python dictionary.

For example:

Feature class name: T14_single_points

New name that I need: Alachua

I am not getting any errors when running this code but I am not getting any results either.

import arcpy

# script to change fc name using a dictionary

arcpy.env.workspace = r"D:\APRX_MXDS\USA_Parcels_2019_Project\test.gdb"
arcpy.env.overwriteOutput = True

fc_list = arcpy.ListFeatureClasses("points*") # list of fc that end with points

# dictionary
county_codes = {14 : "Bradford", 15 : "Brevard", 16 : "Broward"}

for fc in fc_list: # loop through the feature classes
    key = "{[1:3]}".format(fc.name) # let the second and third characters in the fc name be the key
    if key in county_codes: 
        fc = county_codes.get(key) # assign the value in the dictionary as the new feature class name‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

thank you!

Re: Using Python Dictionaries to Change Feature Class Names

DanPatterson_Retired — Sat, 11 Dec 2021 10:41:06 GMT

if len(fc_list) == 0:
    print("something is wrong")‍‍
else:
    print("processing stuff")‍‍‍‍"points*") # list of fc that end with points

could be the issue

wild_card

Limits the results returned. If a value is not specified, all values are returned. The wildcard is not case sensitive.

Symbol	Description	Example
*	Represents zero or more characters.	Te* finds Tennessee and Texas.

did you mean

list of fc that begins with points

or did you mean

"*points") # list of fc that end with points

in any event that might account for one instance where nothing is processed.

Re: Using Python Dictionaries to Change Feature Class Names

JoeBorgione — Thu, 30 Apr 2020 19:24:08 GMT

Hello Natalia Gutierrez- to add to Dan Patterson's comments; I don't see you renaming anything, or is that the next stage in your script?

Re: Using Python Dictionaries to Change Feature Class Names

NataliaGutierrez1 — Thu, 30 Apr 2020 19:29:56 GMT

Hi Joe, I thought I was renaming in the last line of my script. Line # 15. I guess I am really lost with this one...

Re: Using Python Dictionaries to Change Feature Class Names

NataliaGutierrez1 — Thu, 30 Apr 2020 19:30:20 GMT

Thank you Dan that was part of the problem

Re: Using Python Dictionaries to Change Feature Class Names

JoeBorgione — Sat, 11 Dec 2021 10:41:09 GMT

I thought that was what you might be thinking. Take a step back and study your code for a minute, and ask yourself, what exactly is fc?

It's just a variable and the value of that variable changes as the for loop progresses. Run the snippet of code:

for fc in fc_list: 
    key = "{[1:3]}".format(fc.name) 
    if key in county_codes:
        print(fc) 
        fc = county_codes.get(key)
        print(fc)
       ‍‍‍‍‍‍‍

And when it's done, take a look at your geodatabase and see if names have changed.

In order to change the name of the actual feature class, you're going to do a little more work. Take a look Rename—Data Management toolbox | Documentation and see where that takes you.

Re: Using Python Dictionaries to Change Feature Class Names

DanPatterson_Retired — Thu, 30 Apr 2020 20:04:47 GMT

Natalia Gutierrez With that part resolved... what now remains?

Re: Using Python Dictionaries to Change Feature Class Names

DanPatterson_Retired — Sat, 11 Dec 2021 10:41:12 GMT

You are looking for the values, not the keys, which could be the other part of the problem.

Examine the example. Dictionaries are designed to be key-driven... your driver is 2 letters from your county names... aka, the values. There is a workaround, if you must stick to dictionaries.

codes = {14 : "Bradford", 15 : "Brevard", 16 : "Broward"}
kys = codes.keys()
vals = codes.values()
v = [v[1:3] for v in vals]

kys  # ---- dict_keys([14, 15, 16])
vals # ---- dict_values(['Bradford', 'Brevard', 'Broward'])
v    # ---- ['ra', 're', 'ro']

look_for = 'ra'  # ---- Let's look for Bradford, ie, 'ra'

for k, v in codes.items():
    if look_for in v:
        print("found look_for")
    else:
        print("keep looking")
        
found look_for
keep looking
keep looking‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Of course you can skip the dictionary thing and just use nested lists

l = [[14, 'Bradford'], [15, 'Brevard'], [16, 'Broward']]

look_for = 'ra'
for k, v in l:
    if look_for in v:
        print("found {}".format(v))
    else:
        print("keep looking")
        
found Bradford
keep looking
keep looking‍‍‍‍‍‍‍‍‍‍‍‍

And numpy structured arrays are my preference because slicing is enhanced and the operation can be vectorized on whole inputs columns rather than by row... but I will leave that since I am not sure where you are going with this.

Re: Using Python Dictionaries to Change Feature Class Names

NataliaGutierrez1 — Wed, 06 May 2020 20:27:43 GMT

Thank you Dan. In the end I had to do some more research on the topic before I was able to automate this.

Because I needed this very urgent I decided to do it manually since it was taking me to long to automate.

I am using your answer as a guide for the next time I have to do something similar.

Re: Using Python Dictionaries to Change Feature Class Names

NataliaGutierrez1 — Wed, 06 May 2020 20:28:57 GMT

Thank you Joe. As I told Dan, your answers will guide me for the next time I have to work on something similar. In the end I had to do it manually because it was taking me too long to automate it.

Re: Using Python Dictionaries to Change Feature Class Names

JoeBorgione — Wed, 06 May 2020 20:39:33 GMT

Sorry it didn't work out for you; automation can sometimes be a bump in the road. Like anything else though, the more you use it, the better you get at it.

Re: Using Python Dictionaries to Change Feature Class Names

NataliaGutierrez1 — Wed, 06 May 2020 21:21:02 GMT

yes definitely getting a lot better! thanks to you guys in here.

I really appreciate it! I don't know what I would do without your help