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How to zip mat files if they are less than a certain size in a folder?

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Luna
Luna on 12 Mar 2020
Edited: Ameer Hamza on 16 Mar 2020
Hello Dear Community,
I have a folder and I have a lot of mat files in it. Each mat file contains a struct with fields:
name.signals.values
name.signals.dimensions
name.Channelname
name.Channeltype
name.unit
name.timeunit
name.period
name.device
name.time
name.min
name.max
I have more than 300 names for each file. Depending on name.signals.values length, the file sizes change (from 0 to 300 MB). I want to compress those but after compression, the total size of each zip files should not exceed 3 GB. How can I do it? Do you have any ideas?
(Note that I don't want to split to volumes like partially compression.)

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Mohammad Sami
Mohammad Sami on 16 Mar 2020
.mat files are compressed by default. you are unlikely to be able to compress them very much.

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Answers (1)

Ameer Hamza
Ameer Hamza on 16 Mar 2020
Edited: Ameer Hamza on 16 Mar 2020
Try something like this
files = dir('*.mat');
MAX_SIZE = 2.9*2^30; % A bit less than 3GB, to allow for overhead of zip file
[sizes, size_order] = sort([files.bytes]);
file_no = find(cumsum(sizes) > MAX_SIZE, 1);
size_order(file_no:end) = [];
selected_files = files(size_order);
zip('filename', {selected_files.name});
This code read the name and size of all mat files and sort them by sizes. Then zip the files that add up to 3GB starting from the smallest file. I set the MAX_SIZE a bit less than 3GB because mat files are already quite compressed, the zip file cannot compress the further, but it adds a bit of its own overhead.

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