topic How to save every iteration's output from a double for loop in arcpy in Python Questions

How to save every iteration's output from a double for loop in arcpy

CamiSunley — Sun, 22 Nov 2020 21:28:52 GMT

Hello, everyone. I have two sets of similar kind of rasters (1st set: idwlist, 2nd set: equallist) and I want to multiply each raster from the 1st group (‘eachidw’) with every raster from the 2nd group (‘eachequal’). In other words, I want to create a code that calculates and stores all the possible products (multiplications) between the rasters of the two groups.

The problem with the arcpy code below is that the output of every iteration is not saved but overwritten, so I would like to ask if there is any way to make the code save each multiplication output. Thanks a lot !

from arcpy import env

from arcpy.sa import *

import os

arcpy.env.workspace = "C:/MSc_thesis/XrApor"

idwlist = arcpy.ListRasters("*", "TIF")

equallist = arcpy.ListRasters("*", "GRID")

for eachidw in idwlist:

for eachequal in equallist:

outTimes = Times(eachidw,eachequal)

. outTimes.save("C:/MSc_thesis/products")

Re: How to save every iteration's output from a double for loop in arcpy

DavidPike — Sun, 22 Nov 2020 21:45:16 GMT

Logically you would want to save the output file as a combination of the names of the rasters.

I'd grab the names of the rasters before you multiple them, and create a path from that combination.

ensure you import the os module (import os)

from arcpy import env from arcpy.sa import * import os arcpy.env.workspace = "C:/MSc_thesis/XrApor" idwlist = arcpy.ListRasters("*", "TIF") equallist = arcpy.ListRasters("*", "GRID") for eachidw in idwlist: for eachequal in equallist: out_name = eachidw.name + "_" + eachequal.name out_path = os.path.join(r"C:/MSc_thesis/products", out_name) outTimes = Times(eachidw,eachequal) outTimes.save(out_path)

Re: How to save every iteration's output from a double for loop in arcpy

DanPatterson — Sun, 22 Nov 2020 22:17:44 GMT

for i, eachidw in enumerate(idwlist): for j, eachequal in enumerate(equallist): outTimes = Times(eachidw,eachequal) nme = "C:/MSc_thesis/products/" + "raster_{}_{}".format(i, j) . outTimes.save(nme)

in its simplest form. Now if you need the actual names and eachidw and eachequal are short names and not full paths, you can replace, i, j in the format section

Re: How to save every iteration's output from a double for loop in arcpy

CamiSunley — Sun, 22 Nov 2020 23:20:07 GMT

I really appreciate your response. Since I am a beginner in python I am not sure if I replace correctly the elements eachidw.name and eachequal.name you use in the code. Should I use the full path of the first rasters respectively or sth else ? Which is the proper format ? Thanks.

Re: How to save every iteration's output from a double for loop in arcpy

CamiSunley — Mon, 23 Nov 2020 00:03:00 GMT

I tried your suggestion and it works. That was really helpful, thank you very much.