replace only nonzeroes with per-column text and value

I have a vector:

    data = [11,111; 0,222; 33,0; 0,0; 55,555];

I want a string (or char) array like this:

     result:
     ['foo:11,bar:111'; ...
      'bar:222'; ...
      ''; ...
      'foo:44'; ...
      'foo:55,bar:555']

I want to conditionally replace the numbers with strings. If the value is zero I want an empty string. If the value is non-zero I want a prefix for each column and the value.

How do I do this?

strcat cannot do something conditionally. sprintf creates a single horizontal string. string() cannot concatenate.

I'll need `data>0` but then what?

Answer 1

[Star Strider]

Try this:

data = [11,111; 0,222; 33,0; 0,0; 55,555];
strvct = sprintf('foo:%d\tbar:%d\n', data');
result = regexprep(strvct, '(foo:0|bar:0)', '     ')

result =

      'foo:11  bar:111
              bar:222
       foo:33       
                   
       foo:55  bar:555

[Moshe Flam]

Basically your answer is `sprintf` with `\n` I like that.

But I'm waiting to see if someone can come up without the regexp.

I would rather do two replacements, once of the zeroes and once of the nonzeroes and then concat the replacements.

Is there a way to map an action or a conditional action to each cell? If so I can convert to a cell array or string array with the text (of the numbers) and then do the two conditional `replace` and `strcat`.

[Star Strider]

I’m not certain what you want in terms of code.

This seems to be reasonably efficient:

data = [11,111; 0,222; 33,0; 0,0; 55,555];
strvct = sprintf('foo:%d\nbar:%d\n', data');
celvct = regexp(strvct, '\n', 'split');
idx = cellfun(@isempty, regexp(celvct(1:end-1), '(:0)$'));
result = celvct(idx)

result =

    1×6 cell array

      {'foo:11'}    {'bar:111'}    {'bar:222'}    {'foo:33'}    {'foo:55'}    {'bar:555'}