topic Re: Removing characters from rasters and putting them to the front of file name in Python Questions

Removing characters from rasters and putting them to the front of file name

AndrewTuleya2 — Thu, 29 May 2014 12:46:13 GMT

I need syntax in Arcpy/python that will remove "_pa" from the end of any raster file that has this at the end of its file name. Additionally, on files where this is the case, I want to add "PA_" to the front of these files. Can anyone help me?

Thanks.

Re: Removing characters from rasters and putting them to the front of file name

AdamCox1 — Sat, 11 Dec 2021 09:13:05 GMT

Here's some info on the correct tool to use:
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//001700000056000000

Here's an example of how to reconstruct the name:

name = "original_pa"
newname = "PA_" + name[:-3]

Hope that solves it!

Re: Removing characters from rasters and putting them to the front of file name

JamesCrandall — Sat, 11 Dec 2021 09:13:08 GMT

This should get you pretty close to what you need I think.

import arcpy
import os

dir = r'H:\Documents\ArcGIS\Default.gdb'
arcpy.env.workspace = dir

for ras in arcpy.ListRasters("*_pa"):
    print ras #original raster name
    basename = ras.split("_pa")[0] #strip _pa from original raster name
    newrastername = "PA_" + basename 
    print newrastername
    arcpy.CopyRaster_management(ras, newrastername) #create a new raster with the new/updated name

Re: Removing characters from rasters and putting them to the front of file name

AndrewTuleya2 — Thu, 29 May 2014 13:16:07 GMT

Thanks for the reply! What if the file name is not consistent? For example, one raster in the geodatabase is called York_pa and another is Harrisburg_PA, and I want the command to take care of all file names with _pa as the last 3 characters?

Thanks,

Re: Removing characters from rasters and putting them to the front of file name

JamesCrandall — Thu, 29 May 2014 13:22:55 GMT

Thanks for the reply! What if the file name is not consistent? For example, one raster in the geodatabase is called York_pa and another is Harrisburg_PA, and I want the command to take care of all file names with _pa as the last 3 characters?

Thanks,

That's what this does in my solution I provided:

 arcpy.ListRasters("*_pa")

Edit: if you must absolutely ensure that the last 3 characters are evaluated, then you could use the .endswith property. Here's a modified version of my OP:

 for ras in arcpy.ListRasters():     if ras.endswith("_pa"):          basename = ras.split("_pa")[0]         newrastername = "pa_" + basename         arcpy.CopyRaster_management(ras, newrastername)

Re: Removing characters from rasters and putting them to the front of file name

AndrewTuleya2 — Thu, 29 May 2014 13:27:07 GMT

Thanks! Ill give it a go right now.

Re: Removing characters from rasters and putting them to the front of file name

AdamCox1 — Sat, 11 Dec 2021 09:13:11 GMT

The answers above don't take case into account, which is the variation that you mentioned. You should add a .lower() function to the string. This will evaluate the string as a lowercase version of itself. For example:

if ras.lower().endswith("_pa"):
    #rename the raster

Also, I just tested and the split function is case sensitive, so you'll have to watch out for that. What I suggested above works in this way:

name1 = "harrisburg_pa"
name2 = name1[:-3] #remove the last 3 characters, regardless of what they are
name3 = "PA_" + name2 #adds "PA_" to the beginning of the new name

So, regardless of whether or not the raster ends in "_pa", the last three characters will be removed. This may not be desirable, so you may want to filter the rasters by using the if statement that jamesfreddyc suggested. Just be careful because python is case sensitive.

Re: Removing characters from rasters and putting them to the front of file name

Zeke — Sat, 11 Dec 2021 09:13:13 GMT

If you're importing os anyway, you can also use os.rename() rather than copying the raster. Rest is what James & Adam wrote about getting the name correctly.


for ras in arcpy.ListRasters():     
    if ras.lower.endswith("_pa"):             
        basename = ras.split("_pa")[0]         
        newrastername = "pa_" + basename         
        os.rename(ras, newrastername)

Re: Removing characters from rasters and putting them to the front of file name

JamesCrandall — Sat, 11 Dec 2021 09:13:17 GMT

The answers above don't take case into account, which is the variation that you mentioned.

Good catch, although I didn't get that from the OP. But yep case will need to be handled if it is important to the implementation. One minor change could be made using:


if ras.endswith("_pa") or ras.endswith("_PA"):

Re: Removing characters from rasters and putting them to the front of file name

AdamCox1 — Sat, 11 Dec 2021 09:13:21 GMT

Yeah that would work. Usually I use the following format in order to reduce indentation:

for ras in arcpy.ListRasters:
    if not ras.lower().endswith("_pa"):
        continue
    #now you are working with the correct raster, and you can do what you need
    arcpy.management.Rename(ras,"PA_" + ras[:-3])

Though it may be tricky to get all of the auxiliary files if you are using os.rename(), right? I assume that it's not just "raster.tif", but also "raster.tif.xml" and "raster.tfw", or .jpg, etc. If you use the arcpy function, it'll rename all of the associated files at once. Also, if the rasters are stored in a fGDB or something, I don't there's anyway you'd be able to access them with the os module. It all depends on how/where they are stored.

Re: Removing characters from rasters and putting them to the front of file name

JamesCrandall — Thu, 29 May 2014 14:19:28 GMT

If you're importing os anyway, you can also use os.rename() rather than copying the raster. Rest is what James & Adam wrote about getting the name correctly.

os.rename() failed on a GDB raster. But I also tried

arcpy.Rename_management(ras, newrastername)

but it failed with a "table already exists" error.

Re: Removing characters from rasters and putting them to the front of file name

Zeke — Thu, 29 May 2014 14:19:51 GMT

Though it may be tricky to get all of the auxiliary files if you are using os.rename(), right? I assume that it's not just "raster.tif", but also "raster.tif.xml" and "raster.tfw", or .jpg, etc. If you use the arcpy function, it'll rename all of the associated files at once. Also, if the rasters are stored in a fGDB or something, I don't there's anyway you'd be able to access them with the os module. It all depends on how/where they are stored.

I've never used it before, but the Rename function that I linked to above looks super useful.

You may be right. I've used os.rename on rasters, but using os.listdir(). Rename in your link does look promising.

Re: Removing characters from rasters and putting them to the front of file name

AdamCox1 — Sat, 11 Dec 2021 09:13:23 GMT

but it failed with a "table already exists" error.

Sounds like the newrastername already exists in the GDB?

I would do a little inspection of the contents of the GDB, but if you need to remove something before proceeding, this is a useful construction:

if arcpy.Exists(newrastername):
    arcpy.management.Delete(newrastername)

Just be sure to back everything up ahead of time!

Re: Removing characters from rasters and putting them to the front of file name

JamesCrandall — Thu, 29 May 2014 14:32:43 GMT

Sounds like the newrastername already exists in the GDB?

Something was going on in the .gdb I guess, it was weird. After a quick restart the arcpy.Rename_management seems to work. This def looks like a really useful method!

Re: Removing characters from rasters and putting them to the front of file name

hansaneefernando — Fri, 06 Nov 2020 21:55:30 GMT

I used your code for the same application. the code runs fine and won't give me any issues. However I can't find the new rasters. Is there any way we can save the new rasters in a different folder?

My files are like this

20190512_160716_104b_3B_AnalyticMS_SR_clip

20190512_160717_104b_3B_AnalyticMS_SR_clip

This is the code I used

import arcpy
import os
dir = r'D:\My_Canola_Project\1 New Process\Testing 5 Images'
arcpy.env.workspace = dir

for ras in arcpy.ListRasters("*_clip"):
print (ras)
basename = ras.split("_clip")[0]
newrastername = "I_" + basename
print (newrastername )
arcpy.Rename_management(ras, newrastername)

Thanks in Advance

Re: Removing characters from rasters and putting them to the front of file name

MichaelTomiak — Sun, 14 Feb 2021 20:34:22 GMT

What would be the syntax if you just wanted to remove the first X amount of character from the current file name?