Re: strjust

[Ozzy Lash]

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
> _______________________________________________
> Help-octave mailing list
> address@hidden
> https://www-old.cae.wisc.edu/mailman/listinfo/help-octave
>

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.

For example try the following:

octave:4> a = ["notab";"        typedtab";"\tescapedtab";"
eightspaces"]a =

notab
        typedtab
        escapedtab
        eightspaces

octave:5> strjust(a,"left")
ans =

notab
        typedtab
        escapedtab
eightspaces

octave:6> strjust(a,"right")
ans =

              notab
                typedtab
                escapedtab
        eightspaces

octave:7>


Where the "       typedtab" element was typed using ^V^I.  If you look
at the right justification, you'll notice that the two with the tab
don't line up on the right.  I think the tab is being treated as a
single character for alignment purposes, but then is displayed as 8
spaces.

Removing the leading tab would fix this issue, although I suppose
there may still be issues with tabs in the string that aren't at the
beginning of the string.

Bill