Re: strsplit

[Benjamin Abbott]

> On Jun 6, 2014, at 2:58 AM, Juan Pablo Carbajal <address@hidden> wrote:
> 
>> On Fri, Jun 6, 2014 at 2:13 AM, Ben Abbott <address@hidden> wrote:
>>> On Jun 5, 2014, at 8:04 PM, Juan Pablo Carbajal <address@hidden> wrote:
>>> 
>>>> On Fri, Jun 6, 2014 at 2:01 AM, Mike Miller <address@hidden> wrote:
>>>>> On Fri, Jun 6, 2014 at 01:05:53 +0200, Juan Pablo Carbajal wrote:
>>>>> Hi,
>>>>> 
>>>>> Is the following behavior correct in strsplit?
>>>>> 
>>>>> strsplit("/usr/local/share/octave/",filesep())
>>>>> ans =
>>>>> {
>>>>> [1,1] =
>>>>> [1,2] = usr
>>>>> [1,3] = local
>>>>> [1,4] = share
>>>>> [1,5] = octave
>>>>> [1,6] =
>>>>> }
>>>>> 
>>>>> strsplit("/usr/local/share/octave/",filesep(),true)
>>>>> ans =
>>>>> {
>>>>> [1,1] =
>>>>> [1,2] = usr
>>>>> [1,3] = local
>>>>> [1,4] = share
>>>>> [1,5] = octave
>>>>> [1,6] =
>>>>> }
>>>>> 
>>>>> strsplit("/usr/local/share/octave/",filesep(),false)
>>>>> ans =
>>>>> {
>>>>> [1,1] =
>>>>> [1,2] = usr
>>>>> [1,3] = local
>>>>> [1,4] = share
>>>>> [1,5] = octave
>>>>> [1,6] =
>>>>> }
>>>>> 
>>>>> 
>>>>> The output puts an empty cell element when the matching delimiter is
>>>>> at the beginning and at the end.
>>>>> This causes geometry ADD_PKG script to fail, so the behavior changed
>>>>> not long ago (I remember some mails about this, ml compatibility?).
>>>> 
>>>> I see the same behavior in 3.4.3, 3.6.4, and 3.8.1 for this example.
>>>> See also the ostrsplit function in 3.8 which operates like the old
>>>> strsplit.
>>>> 
>>>> Anyway, according to bug #39010 [1], it looks like yes, a string that
>>>> begins and ends with the delimiter should return an empty string from
>>>> both ends.
>>>> 
>>>> [1] https://savannah.gnu.org/bugs/?39010
>>>> 
>>>> --
>>>> mike
>>> 
>>> Thank you fro the quick response and the tests.
>>> 
>>> ok, I guess this is hereditary disease (or can anybody justify this 
>>> behavior?).
>>> If the behavior is so old I wonder how I wasn't getting the failure before.
>>> Anyways I replaced the use of strsplit with fullfile, hopefully this
>>> is more robust and portable.
>> 
>> The commands in Matlab would be ...
>> 
>>        strsplit('/usr/local/share/octave/',filesep())
>>        
>> strsplit('/usr/local/share/octave/',filesep(),'CollapseDelimiters',true)
>>        
>> strsplit('/usr/local/share/octave/',filesep(),'CollapseDelimiters',false)
>> 
>> The third arg for Octave is being taken to be equivalent to Matlab's 
>> "CollapseDelimiters" parameter.
>> 
>> Perhaps Octave's third arg can be made equivalent to "IgnoreEmpties" instead 
>> of "CollapseDelimiters"?
>> 
>> In any event, the old version of strsplit() is still present, but was 
>> renamed.
>> 
>>        ostrsplit('/usr/local/share/octave/',filesep(),true)
>>        ans =
>>        {
>>                [1,1] = usr
>>                [1,2] = local
>>                [1,3] = share
>>                [1,4] = octave
>>        }
>> 
>> Ben
> 
> Thank you Ben,
> As far as I can see there is no mention of the parameter
> "IgnoreEmpties" in the help of strsplit. Is this already implemented
> or is it a missing feature?

It is only a suggested change.

Ben