how to convert a structure array of strings into a string array?

[David Bateman]

Thorsten Meyer wrote:
> Hi,
> 
> I would like to convert a large structure array of strings into a string
> array in a nicely vectorized way.
> 
> for example:
> octave:15> a={"eins", "zwei", "drei"};
> 
> should be converted into
> ans =
> 
> eins
> zwei
> drei
> 
> =================================================
> My first attempt was:
> 
> 
> octave:16> a{:}
> ans =
> 
> (,
>   [1] = eins
>   [2] = zwei
>   [3] = drei
> ,)
> Very nice: this generates a list of strings.
> 
> octave:17> [a{:}]
> ans = einszweidrei
> Here, the elements of the list are concatenated in the wrong way. :-(
> =================================================
> 
> The cat function can concatenate correctly:
> 
> octave:69> cat(1, a{:})
> ans =
> 
> eins
> zwei
> drei
> 
> However, it is incredibly slow for larger arrays and it cannot handle
> strings of different length.

Its faster in 3.1.51+ and is as fast as [a{:}] now.


> =================================================
> 
> This works, but I suppose it's rather slow for large arrays (also it is
> not robust if the strings contains things like "):
> octave:28> eval(["[", sprintf("""%s"";", a{:}), "]"])
> ans =
> 
> eins
> zwei
> drei

I'd probably suggest this way till the a 3.2 release is made, then use cat.

D.

-- 
David Bateman                                dbateman at dbateman.org
35 rue Gambetta                              +33 1 46 04 02 18 (Home)
92100 Boulogne-Billancourt FRANCE            +33 6 72 01 06 33 (Mob)