.... missing valuesI do not exaxtly know you mean by "defining",values
if you just want to replace "0" by missing value after importing your data, the answer is simple: you just highlight all cells which contain "0" and type "--"
(two minus signs) to replace its values. As you will know, you can do this with whole rows or columns with the simple command edit: clear.
if this seems very time consuming to you, it is possible to use set column or Labtalk Scripts. Of course this only works if your data will not contain deliberately set values of zero. Most simple is a set columns command :
set columns.....
col(A)= (col(A)==0) ? silly : col(A)
A (B, C, D , Ei, Blut, Kakao) is the name of the column
this is a simple if then sequence. It checks if a value in the columns is 0. If no it replaces the actual value with the actual value (i.e. does nothing), if yes it replaces 0 with the value of the variable "silly". As you did not set a value to this variable, it has the value "--" .(!?). In other words what you do is cheating Origin with its own bugs. ;->
if you want to set this as a option during import (which is what I would name as definining), I don't know how to do this, but I think this will not work.
Hope this helps, Peter
P.S.: Warum um Himmels willen rechnest Du mit Daten, die Du schon in SPSS hast, noch in Origin rum ?