Break a given MATLAB string into array of sections - matlab

Question

Suppose I have the following string:
%%
a = 2
%%
a =3
%%
t = 0:.1:pi*4;
y = sin(t);
for k = 3:2:9
%%
y = y + sin(k*t)/k;
if ~mod(k,3)
%%
display(sprintf('When k = %.1f',k));
plot(t,y)
end
end
If you notice the third section has nested sections.
I want the output to be
[ 'a = 2', 'a=3' , 't = 0:.1:pi*4; y = sin(t); for k = 3:2:9 %% y = y + sin(k*t)/k; if ~mod(k,3) %% display(sprintf('When k = %.1f',k)); plot(t,y) end end']
How can achieve this using string manipulation?
The problem is using normal regex with '%%' will break the 3rd section into 3 sections.

Answer 1

Assuming the logic behind this is that you want to keep any loops or conditional statements (for, while, and if) together, then you can check for '%%' but also track the number of loops/conditionals you enter and exit.
If you are going through this line by line, then the code would look like this (where the variable tline is the line of text):
% initialize counters
str_count = 0;
in_loop = 0;
% iterate through text lines
while (tline ~= -1)
% check for the %% marker but only increment string counter if not in a loop
if ~isempty(strfind(tline,'%%')) && (in_loop == 0);
str_count = str_count + 1;
else
% if no %% or in a loop, add the current line to the current string
str_set{str_count} = [str_set{str_count} tline];
% check for "for", "if", or "while" and increment the loop counter if found
if ~isempty(strfind(tline,'for ')) || ~isempty(strfind(tline,'if ')) || ~isempty(strfind(tline,'while '))
in_loop = in_loop + 1;
end
% check for "end" and decrement the loop counter if found
if ~isempty(strfind(tline,'end'));
in_loop = in_loop - 1;
end
end
end
Keep in mind that this uses strfind to look for the for, while, if, and end commands (with spaces after the first three). However, it would also pick up words that had those strings at the end (for example, the line xfor = 1; would be picked up). So you either have to add some extra checks or be careful about how you name the variables -- perhaps a better way of looking for those strings is the best. You should see spaces before the words unless they are the first words, and could add conditions to that effect.