Cody Problem 41. Cell joiner, not sure why spaces aren't showing

I'm working on Cody Pr 41 and I think I had a solution

function out_str = cellstr_joiner(in_cell, delim)
out_str = strcat(in_cell(1))
for i = 2:length(in_cell)
    out_str = strcat(out_str, delim , in_cell(i))
end
end

but the delim isn't showing when it's equal to '', but it will show if its equal to '?'

Any ideas why?

Answer 1

[the cyclist]

The code

''

will not be a space. It will be null. The code

' '

will be a space. Does that help?

[Joe Smith]

No, didn't make a difference. I put ' ' up to ' ' still the same.

Answer 2

[the cyclist]

So, I peeked into the code for strcat, and see these lines

    if ~isempty(str) && (str(end) == 0 || isspace(str(end)))
        str = char(deblank(str));
    end

(in lines 82-84) of the code.

So, the code is "deblanking", even when you are explicitly trying to append a white space.

This was certainly not obvious to me in the documentation, but it is definitely what the strcat code is intending to do.

[Steven Lord]

See the third paragraph in the Description section of the documentation for strcat. If you're using release R2013a or later, consider using strjoin instead.

[the cyclist]

Hey, Steven. I did read and mull the documentation prior to my post. I don't really think that paragraph describes his situation.

First, he is inputting cell arrays, not character arrays, so the paragraph you reference isn't relevant.

Second, this is not exactly "trailing" whitespace, because he is doing a concatenation of the form

strcat('s1',' ','s2')

So, I agree with you that I can retroactively understand the documentation for his situation, but I don't think I would have anticipated this behavior.