Re: set no value to []?

[Etienne Grossmann]

  Hello,

From: Daniel Heiserer <address@hidden>
#  Despite matlab incompatibility and  
#  incompatibiltiy to current m-files
#  is there  another reason for not
#  setting values of a function which
#  are undefined to []?

  [] may be a valid argument. I often use 'nan' where you use [], for
that reason. 'Nan' could be a valid argument for some functions too,
of course.

#  Assume I have a function
#  #----
#  function [o1,o2,o3,o4]=django_1(i1,i2,i3,i4)
#  #....
#  #------

#  And I want to call it whith lets say no value for i2.
#  Currently I have to mess around with nargin and so on.
#  But if I want to be able to call this function 
#  with no i2 OR no i3 and the parameters are of the same
#  type it is hard to impossible to distinguish if I tried to
#  call without i2 or i3.

  You can use option-like arguments, but that's slow : 

  [o1,dummy,o3,o4] = django_1 (i1, i2, "i4", i4);
                                        ^    ^
                                 "Option"    Argument

  I have a "read_options" script for that, but it is clumsy.
                                           

#  Assume omitting i2 gives no result for o2 and omitting
#  i3 gives no result for o3:
#  I think it would be MUCH cleaner then to call the function 
#  then like
#  [o1,,o3,o4]=django_1(i1,,i3,i4);
#     --                  --

  In that case, you could use variable length return list. Function
could be declared as : 

  [...] = django (i1,i2,...)

  and then use vr_add ().

  Cheers,

  Etienne



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