Re: strjust

[Ben Abbott]

On Oct 15, 2010, at 3:39 AM, Jaroslav Hajek <address@hidden> wrote:

> On Fri, Oct 15, 2010 at 9:14 AM, Leo Butler <address@hidden> wrote:
>> 
>> 
>> On Thu, 14 Oct 2010, Ozzy Lash wrote:
>> 
>> < On Thu, Oct 14, 2010 at 4:42 PM, Ben Abbott <address@hidden> wrote:
>> < > On Oct 14, 2010, at 1:58 PM, Ozzy Lash wrote:
>> < >
>> < >> On Thu, Oct 14, 2010 at 3:06 PM, Ben Abbott <address@hidden> wrote:
>> < >>>
>> < >>> On Oct 14, 2010, at 12:20 PM, Ozzy Lash wrote:
>> < >>>
>> < >>>> On Thu, Oct 14, 2010 at 10:36 AM, Ben Abbott <address@hidden> wrote:
>> < >>>>> On Oct 14, 2010, at 7:03 AM, Leo Butler <address@hidden> wrote:
>> < >>>>>
>> < >>>>>> On Wed, 13 Oct 2010, Ben Abbott wrote:
>> < >>>>>>
>> < >>>>>> < On Oct 13, 2010, at 12:16 AM, Leo Butler <address@hidden> wrote:
>> < >>>>>> <
>> < >>>>>> < > In 3.3.52+, I find the following behaviour of strjust,
>> < >>>>>> < > which appears to conflict with its description.
>> < >>>>>> < >
>> < >>>>>> < > octave> s=sprintf("\tstring");
>> < >>>>>> < > octave> s=strjust(s,"left")
>> < >>>>>> < > s =     string
>> < >>>>>> < > octave> s=sprintf("        string");
>> < >>>>>> < > octave> s=strjust(s,"left")
>> < >>>>>> < > s = string
>> < >>>>>> < >
>> < >>>>>> < > You can see that it is not removing leading tabs.
>> < >>>>>> < >
>> < >>>>>> < > Leo
>> < >>>>>> <
>> < >>>>>> < Does the description below clarify how strjust functions?
>> < >>>>>> <
>> < >>>>>> < strjust (S)
>> < >>>>>> < strjust (S, "right")
>> < >>>>>> < Returns the text, S, justified to the right.
>> < >>>>>> < strjust (S, "left")
>> < >>>>>> < Returns left justified text.
>> < >>>>>> < strjust (S, "center")
>> < >>>>>> < Returns center justified text.
>> < >>>>>> < Null characters are replaced by spaces.
>> < >>>>>>
>> < >>>>>> Here is the info description:
>> < >>>>>>
>> < >>>>>>  -- Function File:  strjust (S, ["left"|"right"|"center"])
>> < >>>>>>       Shift the non-blank text of S to the left, right or center of 
>> the
>> < >>>>>>       string.  If S is a string array, justify each string in the 
>> array.
>> < >>>>>>        Null characters are replaced by blanks.  If no
>> < >>>>>>        justification is
>> < >>>>>>      specified, then all rows are right-justified.
>> < >>>>>>
>> < >>>>>> By comparison:
>> < >>>>>> -- Function File:  strtrim (S)
>> < >>>>>>      Remove leading and trailing blanks and nulls from S.
>> < >>>>>>
>> < >>>>>> And here is how each works:
>> < >>>>>>
>> < >>>>>> octave> s=sprintf("\tstring");
>> < >>>>>> octave> strjust(s,"left")
>> < >>>>>> ans =   string
>> < >>>>>> octave> strtrim(s)
>> < >>>>>> ans = string
>> < >>>>>>
>> < >>>>>> You see that the definition of 'blank' is inconsistent.
>> < >>>>>>
>> < >>>>>> Leo
>> < >>>>>
>> < >>>>> I've pushed the change below.
>> < >>>>>
>> < >>>>> http://hg.savannah.gnu.org/hgweb/octave/rev/04c3aacbbc46
>> < >>>>>
>> < >>>>> Thanks
>> < >>>>> Ben
>> < >>>>>
>> < >>>>
>> < >>>> I think I agree with Leo, and that tabs should be treated as
>> < >>>> whitespace (or blanks) and should be stripped for justification,  If
>> < >>>> not, I think that there is an issue for right justification as well.
>> < >>>>
>> < >>>
>> < >>> Ok. I hadn't realized Leo was asking that the way strjust() works 
>> should be changed.
>> < >>>
>> < >>> How might strjust() be modified and remain compatible with Matlab?
>> < >>>
>> < >>> Ben
>> 
>> Ben, thanks for looking into this.
>> 
>> To clarify: my original email was a genuine inquiry, not a request
>> for change. However, would it not be possible to modify strjust so that
>> the definition of whitespace can be input by the user, e.g.
>> 
>> strjust(string,"left",[9,32])
>> strjust(string,"right",[" ","\t"])
>> 
>> The default behaviour need not change.
>> 
>> Leo
>> 
> 
> 
> The problem is that tab is very seldom treated as equivalent to a
> single space (or null in this case, which was included for
> compatibility). Usually it's eight or two or whatever. I believe
> that's why it was excluded here. I suggest you use strrep (possibly
> combined with cellstr/strvcat) to replace tabs by whatever amount of
> spaces you consider appropriate, and then use strjust.
> 
> hth

Would a tab_to_spaces() be a good idea?

Ben