How to insert a variable into a tool script

Question

I am a bit new when it comes to Python programming.

I'm trying to run the GRASS r.sun plugin tool to calculate the global irradiance for my chosen area for the whole year. The problem is that r.sun calculates the irradiance for a day. The GRASS program isn't an option for me becouse it doesn't work properly on my computer.

So the solution that I am looking for is a script that puts every number from 1 to 365 into the tool and makes a .tif raster result with the number of the day in its name. The numbers that have to change are in bold.

Basically this but in python:

https://grasswiki.osgeo.org/wiki/R.sun#Automation

Example of script taken from History:

import processing

dir(processing)

elev_raster = "C:\Qgis_proj\data\DSM.tif"

aspect_raster = "C:\Qgis_proj\pod\aspect.tif"

slope_raster = "C:\Qgis_proj\pod\slope.tif"

irradiance_raster = "C:\GRASS\results\glob_irr_1.tif"

processing.runalg("grass7:r.sun",elev_raster, aspect_raster, slope_raster,None,None,None,None,None,None,1,0.5,0,1,False,False,"454999.5,457000.5,95999.5,98000.5", 0,None,None,None,None, irradiance_raster)

Answer 1

Basically, you just have to add a for loop. The following code should work:

import processing
dir(processing)
elev_raster = "C:\Qgis_proj\data\DSM.tif"
aspect_raster = "C:\Qgis_proj\pod\aspect.tif"
slope_raster = "C:\Qgis_proj\pod\slope.tif"
for i in range(1,365):
 irradiance_raster = "C:\GRASS\results\glob_irr_" + str(i) + ".tif"
 processing.runalg("grass7:r.sun",elev_raster, aspect_raster, slope_raster,None,None,None,None,None,None,i,0.5,0,1,False,False,"454999.5,457000.5,95999.5,98000.5", 0,None,None,None,None, irradiance_raster)

• Shai-Hulud: Thank you very very much :) I knew the range would be useful.
• Robin: If you want fancier filenames (e.g. zero padding), have a look at docs.python.org/3/tutorial/inputoutput.html. E.g. str(i).zfill(3) instead of str(i) gives '001', '002' etc. filenames. Also the format() method for strings is nice. '{0:03d}'.format(i) instead of str(i) again gives '001', '002' etc.
• ArMoraer: @Robin: nice catch! I didn't know zfill.