combining different cell arrays into one in MATLAB - arrays

Question

I am trying to look for specific characters in an array and print the output into an excel sheet in the same order (i.e if there are elements in between without a match it is left blank).
I used the following code within the loop:
EDIT:
[num,txt,~] = xlsread('protein-peptides.xls')
for i=1:size(txt)
str(i)=txt(i)
expression='\w*Pyro-glu from E\w*';
matchStr(i)=regexp(str(i),expression,'match','once');
ArrayOfStrings=vertcat(matchStr{:});
end
After the loop:
xlswrite(filename,ArrayOfStrings,1);
And the output is like below.
1) The elements without a match are not shown as blank
2) Each word of the match is displayed in a different cell.
P y r o - g l u f r o m E
P y r o - g l u f r o m E
P y r o - g l u f r o m E
P y r o - g l u f r o m E
How do I get the blank spaces left out in the matrix and have the entire matching phrase in a single cell in the output?
I tried concatenation of cells but that is printing all the output in a single row but still each character in different cells

Answer 1

I know you'd probably prefer to use xlswrite, but I wasn't able to get this to work (at least on OS X). It appears that xlswrite automatically strips out empty cells, as you observed. It also appears to be spreading each cell over multiple columns, which is bizarre and different from the behavior I remember. I wonder if there was a recent update (I'm using R2015b).
I was able to get this to work using simple fprintf calls to write a CSV file, which can be opened in Excel. Note that the termination character (\r) is critical; empty cells do not seem to be preserved in Excel if this is replaced by a linefeed. I also refactored your code a bit.
% Load data from Excel file
[~, txt, ~] = xlsread('protein-peptides.xls');
% Perform analysis
expression='\w*Pyro-glu from E\w*';
for i = 1:length(txt)
matches(i, 1) = regexp(txt(i), expression, 'match', 'once');
end
% Write data to CSV file
fid = fopen('test.csv', 'w+');
for i = 1:length(matches)
fprintf(fid, '%s\r', matches{i});
end
fclose(fid);
Input file rows
Pyro-Flu from E
test
Pyro-Flu from E
test
Output file rows
Pyro-glu from E
Pyro-glu from E