[Octave-bug-tracker] [bug #42023] dlmread doesn't honor 'emptyvalue' value for empty delimiter

[Philip Nienhuis]

URL:
  <http://savannah.gnu.org/bugs/?42023>

                 Summary: dlmread doesn't honor 'emptyvalue' value for empty
delimiter
                 Project: GNU Octave
            Submitted by: philipnienhuis
            Submitted on: Tue 01 Apr 2014 10:44:32 PM CEST
                Category: Libraries
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: Philip Nienhuis
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: dev
        Operating System: Any

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Details:

(Not sure if I fully understand dlmread's behavior but here goes:)

File imp2a.txt:

aaaa 11
bbbb 
cccc 33

(note trailing space on L.2 after bbbb)

>> dlmread ('imp2a.txt', ' ', 0, 1, 'emptyvalue', NaN)
ans =

    11
   NaN
    33

##.............OK, the expected result

>> dlmread ('imp2a.txt', '', 0, 1, 'emptyvalue', NaN)
ans =

   11
    0
   33

##.............?? expected (hoped for) NaN rather than 0 in L.2


Note the only difference is an empty delimiter in the second call.
dlmread's behavior for this case of an empty delimiter isn't described in
dlmread's help. I suppose it's meant, like in Matlab, to treat multiple
consecutive spaces as one delimiter.

Now consider file imp2b.txt:

aaaa 11
bbbb 
cccc 33

(same as imp2a.txt but now w/o trailing space on L.2)

>> dlmread ('imp2b.txt', '', 0, 1, 'emptyvalue', NaN)
ans =

   11
    0
   33

>> dlmread ('imp2b.txt', ' ', 0, 1, 'emptyvalue', NaN)
ans =

   11
    0
   33


Here, both dlmread calls (with empty and with space delimiter) yield results I
didn't expect (hope for).

As to ML: that doesn't have the 'emptyvalue' parameter; calling dlmread (w/o
'emptyvalue' parameter) in ML gets me
11
 0
33
for all four cases above.


Background: I'm trying to get importdata.m more ML-compatible. To that end,
dlmread should return proper NA values when called with '"emptyvalue", NA' and
an empty delimiter.
The importdata.m incompatibility is this:

Octave:

>> res = importdata ('imp2a.txt', ' ')
res =

  scalar structure containing the fields:

    data =

       11
        0
       33
<snip>


where ML r2014a gives:

>> res.data
ans =
    11
   NaN
    33






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