Conditional won't work on GrassGIS python script

Question

I have a conditional in Python script from GRASS but I can not get it to work. No matter if I set m to 1 or 0 it always prints "m must be 1 or 0." like it won't enter the conditional.

Here's the script:

m=options['m']
if m==1:
 grass.mapcalc("up=$c+tan($phy)*(($gamma*$z*(cos(slope)^2))-($k*$gamma*$z*sin(slope)*cos(slope))-($z*$gammaw))",
 z = options['z'],
 c = options['c'],
 gamma = options['gamma'],
 phy = options['phy'],
 k = options['k'],
 gammaw = 9.81)
 print ('m is 1')
elif m==0:
 grass.mapcalc("up=$c+tan($phy)*(($gamma*$z*(cos(slope)^2))-($k*$gamma*$z*sin(slope)*cos(slope)))",
 z = options['z'],
 c = options['c'],
 gamma = options['gamma'],
 phy = options['phy'],
 k = options['k'])
 print ('m is 0')
else:
 print("m must be 1 or 0.")

Answer 1

You probably need to convert it to number:

m = int(options['m'])

But it looks like you want to define it as a flag instead of option, since it can be only True or False, so then you would use it as:

if flags['m']:
 # do something
else:
 # do something else

See also the manual: https://grass.osgeo.org/grass74/manuals/g.parser.html

• Federico Gómez: Thank you Anna, i did thought it was something simple but I was really stuck. Thanks for your help!