# Loop that names first 3 files one name and 2nd 3 files another.

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Jonathan Marchetto on 14 Nov 2018
Commented: Mark Sherstan on 16 Nov 2018
Having a tough time doing something that is likely rather simple.
I have a folder with files, lets say they are named AAA.XLS, BBB.XLS, CCC.XLS.
I want to take half of the AAA.XLS files and rename them DDD.XLS. The files are stored so that there are 3AAA files in a row that will be kept AAA, followed by 3 files in a row that should be changed to DDD.
I have the code correct ( I believe) other than the for loop. I know how to loop every nTH iteration, but I want to do it in chunks so to speak with 3 on/3off.
Below is the code without the for loop
A =dir( fullfile(a, '*.xlsx'));
fileNames = { A.name };
for iFile = 1 : numel( A )
newName = fullfile(a, sprintf( '%03AAA.xlsx', iFile ) );
movefile( fullfile(a, fileNames{ iFile }), newName );
end

Mark Sherstan on 14 Nov 2018
Edited: Mark Sherstan on 14 Nov 2018
If I understand your question correctly try implementing one of the two codes to solve your problem:
for i = 1:numel(A)
if mod(i,3) == 0
doSomething(i);
continue
end
doSomethingElse(i);
end
for i = 1:3:numel(A)
doSomething(i);
end

Jonathan Marchetto on 16 Nov 2018
Thanks for the help.
This code gives me 1, 4, 7, 10, etc when I am interested in getting 1,2,3,7,8,9,etc basically 3 on 3 off if that makes sense.
Mark Sherstan on 16 Nov 2018
Sorry for the confusion! Here is a working correction:
flag = true;
for ii = 1:20
if flag == true
% Put code here
fprintf('%0.0f\n',ii)
end
if mod(ii,3) == 0
flag = ~flag;
end
end
Output is:
1
2
3
7
8
9
13
14
15
19
20