My version of QGIS is 2.8.3

I have a tool which takes parameters like this:

##Distance=number 1.0
##Height=field Input_Vector_Layer

# Do Something...

Is it possible to make the fourth parameter optional?

  • 2
    Have you tried ##Height=optional field Input_Vector_Layer?
    – Joseph
    Dec 7, 2016 at 10:02
  • Just tried but did not work, it gives me this : 'Problem with line: %d', 'ScriptAlgorithm') % (self.descriptionFile, line)) TypeError: %d format: a number is required, not str Dec 7, 2016 at 10:15
  • @user80597, did my solution work for you?
    – mgri
    Dec 7, 2016 at 11:29
  • @HowToInQGIS It does work, though it is not the exact thing I am look for, I think this might be the best I can do in v2.8... Dec 7, 2016 at 20:08

1 Answer 1


If it's not a problem for you, my idea is to add a Boolean:

##Distance=number 1.0
##Height=field Input_Vector_Layer
##Use_Optional_Field=Boolean True

and the directly check for its value:

check = Use_Optional_Field
if check:
    # Do something...
    # Do something else
  • This is probably the best method to emply using QGIS 2.8 =)
    – Joseph
    Dec 7, 2016 at 13:28
  • 3
    As suggested by @Joseph , the optional field parameter only works for more recent versions.
    – mgri
    Dec 7, 2016 at 13:39

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