Re: inconsistent results between textread and load

[Philip Nienhuis]

kamaraju wrote
> It looks like the same data file is read in different ways by textread
> and load. Is this intentional? If not, can we make the default
> behaviour consistent?
> 
> Consider the following two data files
> 
> address@hidden:~/x$ cat data.txt
> 1.0 2.0 NaN 3.0 4.0
> address@hidden:~/x$ cat data2.txt
> 1.0 2.0 NA 3.0 4.0
> 
> address@hidden:~/x$ octave -q
> octave:1> a = textread("data.txt"); a
> a =
> 
>      1
>      2
>    NaN
>      3
>      4
> 
> octave:2> a = load("data.txt"); a
> a =
> 
>      1     2   NaN     3     4
> 
> So textread is reading it as a 5x1 vector while load is reading it as
> 1x5 vector.
> 
> octave:3> a = load("data2.txt"); a
> error: value on right hand side of assignment is undefined
> octave:3> a = textread("data2.txt"); a
> a =
> 
>      1
>      2
>     NA
>      3
>      4
> 
> So 'load' is not able to handle NA but 'textread' is.

I'm not sure about "load" and NA. Hopefully other people here will comment
on that.

As to the output format (dimensions):
You made a data file consisting of one row. In that case textread, having
been given no format string, will by default read the numbers consecutively
and produce a 1-column output vector.
It would have been different had you supplied a format string "%f %f %f %f
%f".

To illustrate that, I've run your example with strread (the work horse
behind textread, for the outcome that doesn't matter):

>> [a] = strread ("1.0 2.0 NaN 3.0 4.0")
a =

     1
     2
   NaN
     3
     4

>> [a, b, c, d, e] = strread ("1.0 2.0 NaN 3.0 4.0", "%f %f %f %f %f")
a =  1
b =  2
c = NaN
d =  3
e =  4

>> [a, b, c, d, e] = strread ("1.0 2.0 NaN 3.0 4.0 \n 5 6 7 NaN 8", "%f %f
>> %f %f %>
a =

   1
   5

b =

   2
   6

c =

   NaN
     7

d =

     3
   NaN

e =

   4
   8


I'd suggest to read up on textread's (strread's) format string and defaults.

Philip



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