[NeXus-code-tickets] [NeXusCode] #156: python: support '|S1' for string data

[NeXus Data Format Library and Applications]

#156: python: support '|S1' for string data
-----------------------+----------------------------------------------------
  Reporter:  Cpascual  |       Owner:  Paul Kienzle     
      Type:  defect    |      Status:  new              
  Priority:  minor     |   Milestone:  NeXus 4.2 Release
 Component:  bindings  |     Version:  4.2rc2           
Resolution:            |    Keywords:  numpy dtype char 
-----------------------+----------------------------------------------------
Comment (by Cpascual):

 The ability to deal with numpy string arrays as the **input** would be
 interesting for two reasons:

 1) It makes the API more consistent (one would not need act differently
 depending on whether is using 'char' or other types)

 2)It paves the path to multidimensional character arrays.



 Regarding the **output**: IMHO, the output should be always the same
 regardless of the input, and only dependent on the data shape (i.e., on
 what is returned by NXgetinfo(). I think that the most consistent option
 is to always return a numpy array of strings:

 If the data shape is [m], then the output should be a zero-dimensional
 numpy array containing a string of length m

 If the data shape is [n,m], then the output should be a n-long 1D numpy
 array of strings of length m.

 If the data shape is [k,n,m] then the output should be a 2D array [with
 shape=(k,n)] of strings of length m.

 ...

 As an exception it could be reasonable to implement it in such a way that
 data with shape [m] returns a python string instead of a numpy array of
 shape=(,). But, IMHO, always returning numpy makes it more self-
 consistent. The user can always convert the output (or slices of it) to
 strings using the .tostring() method of the numpy arrays.

 I am currently working on my own implementation of this. I will post it as
 soon as it is ready.

-- 
Ticket URL: <http://trac.nexusformat.org/code/ticket/156#comment:4>
NeXus Data Format Library and Applications <http://www.nexusformat.org/>
NeXus Data Format Library and Applications