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Home > Troubleshooting > UR script multiple returns
dannyhef

Hey everybody,

does anybody know if it is possible to return multiple values in a ur script def() function like return[x,y,z]. It only worked for me to return one value.

Thanks,
Dan
bcastets

Maybe you could return several values by returning them in a list ?
matthewd92

you can return a list, the list must be of the same type for all list elements. You can only return numbers, poses and booleans in a list. 
dannyhef

Thanks for the answer. So it is not possible to return more than one variable like return [Var_1, Var_2] and do something like in python [Var_1, Var_2] = function. So I have to put var_1 and var_2 in a list like var_3 = [var_1,var_1] and then return it, return var_3. But if var_1 and var_2 is a list this var_3 = [var_1,var_1]  would not work. Right?
matthewd92

You can return the list directly but there are limited types that can be in the list. 


Here’s an example that would work as the values are of the same type and they are numbers

def describeCircle(radius):
  local circumference = 6.28*radius
  local area = 3.14*radius*radius
  return [circumference,area]
end

This would not work as center is a point, either list or pose, and radius is a number so types are mismatched. 

def describeCircle(a,b,c):
  local center = findCenter(a,b,c)
  local radius = findRadius(a,b,c)
  return [center,radius]
end
bcastets

Never tried it but maybe it is possible to return different types by returning a list of list :smile:

[[point],[value],[...]]
dannyhef

Thanks Matthew,

I tried it the way you did. 

def describeCircle(radius):

  local circumference = 6.28*radius
  local area = 3.14*radius*radius
  return [circumference,area]
end

and then I tried to call/store the new variables and this didn't work.

[circumference, area] = describeCircle(radius)
matthewd92

Yeah, it won’t spread them like that. You would have to do this. 


local values = describeCircle(radius)
local area = values[1]
local circumference = values[0]

Or I could use them like this 

local volume = getVolumeFromAreaAndHeight(values[1], height)
matthewd92

bcastets said:
Never tried it but maybe it is possible to return different types by returning a list of list :smile:

[[point],[value],[...]]
Unfortunately a list is not a supported list element type, sucks since a pose (modified list) is a supported list element type