function only using one return for argument

Question

My combine function appears to only be using one return out of the three I want to use as arguments. I receive the following error message

Error: combine_lists() takes exactly 3 arguments (1 given)

how can I resolve this?

Removing references to ikw and ikpv keeps me from getting the error. It thought I could use multiple returns from different functions in this manner but maybe not?

code for my button:

cmds.button(label='IK 2 FK',  command = combine_lists, width=100)

def select_joints_afk():
    Fks = []
    del Fks[:] 
    if cmds.ls(selection = True,type=("transform",'nurbsCurve')):
        sel = cmds.ls(sl=True)
        fkCtrls = cmds.listRelatives(sel, allDescendents=True, type=("transform",'nurbsCurve'))
        Fks = [nurbsCurve for nurbsCurve in fkCtrls if nurbsCurve.startswith('FK') & nurbsCurve.endswith('Ctrl')]
        cmds.textFieldButtonGrp(gtF0, edit = True, tx ='' .join(sel),buttonLabel='IK OK',backgroundColor = (.5,.8,.2))
        del Fks[1]
        del Fks[2]
        Fks.extend(sel)

        print Fks[0]
        print Fks[1]
        print Fks[2]
        return Fks 
    else:
        text = cmds.confirmDialog( title='Error', message='Must select joint', button=['OK'], defaultButton='Ok', dismissString='No' )


def select_joints_aikw():
    ikw = []
    del ikw[:]
    if cmds.ls(selection = True,type=("transform",'nurbsCurve')):
        ikwrist=cmds.ls(selection = True)
        ikw = [nurbsCurve for nurbsCurve in ikwrist if nurbsCurve.startswith('IK') & nurbsCurve.endswith('Ctrl')]
        cmds.textFieldButtonGrp(gtF1, edit = True, tx ='' .join(ikwrist),buttonLabel='IK OK',backgroundColor = (.5,.8,.2))
        print ikw
        return ikw
    else:
        text = cmds.confirmDialog( title='Error', message='Must select joint', button=['OK'], defaultButton='Ok', dismissString='No' )

def select_joints_ikpv():
    ikpv = []
    del ikpv[:]
    if cmds.ls(selection = True,type=("transform",'nurbsCurve')):
        ikPvsel = cmds.ls(selection = True)
        ikpv = [nurbsCurve for nurbsCurve in ikPvsel if nurbsCurve.startswith('IK') & nurbsCurve.endswith('Ctrl')]
        cmds.textFieldButtonGrp(gtF2, edit = True, tx ='' .join(ikPvsel),buttonLabel='IK OK',backgroundColor = (.5,.8,.2))        
        print ikpv
        return ikpv
    else:
        text = cmds.confirmDialog( title='Error', message='Must select joint', button=['OK'], defaultButton='Ok', dismissString='No' )

def combine_lists(Fks,ikw,ikpv):


    Fks =  select_joints_afk()

    ikw = select_joints_aikw()

    ikpv = select_joints_ikpv()


    print Fks+ikw+ikpv

Answer 1

You have

def combine_lists(Fks,ikw,ikpv)

which means whenever you call combine_lists() you need to pass it three arguments.. i.e. combine_lists(x, y, z). It looks like you are just using combine_lists to calculate those three things and you are not trying to pass it anything.. so just do:

def combine_lists():


   Fks =  select_joints_afk()

   ikw = select_joints_aikw()

   ikpv = select_joints_ikpv()


   print Fks+ikw+ikpv