I have some data generated in MATLAB that I want to process using Perl. I saved the data from MATLAB in a .mat file. Is there any way to read it in Perl?
One option would be to save the binary MAT file as ASCII from inside MATLAB using something like:
load('test_data.mat');
save('test_data.asc', 'var1', 'var2', '-ascii');
Then you would have ASCII data to process in Perl.
If you need a solution completely written in Perl, then you should be able to automate the process using the Math::MATLAB package on CPAN.
NOTE: If Python is an option, you could use the loadmat function in the SciPy Python library.
The Java library JMatIO has worked well for me. Maybe you can try using inline Java.
Related
I have a consistent bpmn file (similar to xml file) and i would like to read it with matlab and store the all file data in one string or char attribute. I have tried with textread(file, format) but the best i can have is a 2358796x1 char and then assemble each line to recreate the file but it's a very long process.
Is there another function to do this ?
Thanks for helping.
You can use this xml2struct.m function, to read xml files and convert all the content to MATLAB struct variable.
Newer versions of Matlab ship with an xmlread function. Have you taken a look at that?
I have just started to use MAPLE. I am a matlab user.
In matlab I can use any matlab function(.m file) written in same directory.
Could someone help me out how I can do same with MAPLE. I have few worksheets performing some tasks(all in same directory)
I need to use those functions and write my own code.
Thanks in advance
Have you looked at packages? They use the same module structure as objects, but for a different purpose - they are meant to make code reusable.
A package can be maintained as source file and then be read from the current directory by its filename: read("MyModule.mpl"). This seems similar to what you are used from matlab, except that you would have to load the module explicitly. Alternatively it can be saved as binary *.mla file (Maple library archive) somewhere on the library path, then loaded by its exported package name from anywhere: with(MyModul).
Can I read an excel file without using any module?
I tried like just reading a normal file and it printed binary characters; maybe because of encoding?
But reading csv files is working normally.
Excel files are binary files, and the format of the pre-2007 ones is apparently quite hairy. I believe .xlsx files are actually zipped XML, so unzipping them should yield something human-readable, but I've never tried it. Why do you want to not use a module though?
Some further reading, if you're interested:
http://joelonsoftware.com/items/2008/02/19.html
http://en.wikipedia.org/wiki/Office_Open_XML_file_formats
Can I read an excel file without using any module?
In theory yes. In practice no.
An Excel XLS file is a binary file within a binary file. The first step would be to parse the Excel BIFF data out of the OLE COM document container. This data isn't necessarily in sequential order.
Then you have to parse the Excel BIFF data, allowing for differences between versions, a shared string table with different encodings and CONTINUE blocks that map large data records in a parser unfriendly way.
The Excel XLSX format is a little easier since it is a collection of XML files in a Zip container. However, if you aren't using modules then even that would be a pain.
The Perl modules that deal with Excel files represent hundreds of man hours of work. Expect to invest a similar amount of work to avoid them.
And why can't you use modules?
You can try figuring out the format of what an Excel spreadsheet looks like, code for that, and then use that in your program. Maybe write it as a module and submit it to CPAN. Wait a second! There's already a module like that there!
The whole purpose of CPAN is to prevent you from having to reinvent the wheel. You need to read an Excel spreadsheet, and someone has done the hard work to figure out how to do this, and is giving it to you free of charge. A $40,000 value1, and it's yours for free! The CPAN system makes installing modules fairly simple. You run the cpan command. There's no real reason to avoid modules that can save you hundreds of hours of work.
And, what type of modules do you avoid? Is it all modules, or is it only modules that are not included in the standard distribution. I hate to think you don't use things like File::Copy or Data::Dumper just because they're modules even though they're included by default in most Perl distributions.
1 Imagine hiring a team to write code to convert an Excel file, so it can be read by a Perl program. They'd have to figure the ins and outs of the file format, code for all sorts of edge cases, and run it through all sorts of tests to make sure it really works. A rough estimate if we don't include things like charts, embedded content, and remote data access would be about 200 man-hours, but only because it's actually has been documented.
Has anyone ever heard of something that might facilitate the work with XMP metadata in Matlab?
For instance, EXIF metadata can be read simply by using the exifread command -
output = exifread(filename);
I've found this thread, but it seems to be dead.
Currently I am thinking about the following options:
Writing MEX file using C++ XMP SDK
Calling Java routines using JAVA XMP SDK
To summarize, the question is:
Do you have any idea on how XMP can be read/written in Matlab?
XMP is just XML, so you can use any MATLAB XML toolbox. My personal favourite is xml_io_tools.
If you want to use the SDK to avoid having to manually interpret what bits of the XML means, then of your two options the Java one sounds preferable. Calling Java from MATLAB is straightforward, and you avoid the hassle of building things that MEX entails.
I have found the answer. The best way is to download ExifTool and any Matlab JSON parser. It is possible to extract it from any file format, including .DNG, .XMP, .JPEG, .TIFF.
Step 1: Extract the info into temporary JSON file by using
system(['exiftool -struct -j ' fileName '>' tempFile]);
Step 2: Call the JSON parser on the tempFile
Step 3: You have the data in Matlab struct.
I've downloaded a data set that I am interested in. However, it is in .mat format and I do not have access to Matlab.
I've done some googling and it says I can open it in SciLab.
I tried a few things, but I haven't found any good tutorials on this.
I did
fd = matfile_open("file.mat")
matfile_listvar(fd)
and that prints out the filename without the extension. I tried
var1 = matfile_varreadnext(fd)
and that just gives me "var1 = "
I don't really know how the data is organized. The repository described the data it contains, but not how it is organized.
So, my question is, what am I doing wrong in extracting/viewing this data? I'm not committed to SciLab, if there is a better tool for this I am open to that.
One options is to use Octave, which can read .mat files and run most Matlab .m files. Octave is open source with binaries available for Linux, Mac, and Windows. Inside of Octave you can load the file using:
load file
See Octave's manual section 14.1.3 Simple File I/O for more details.
In Scilab:
loadmatfile('file.mat');
(Source)
I had this same interest a few years back. I used this question as a guide. It uses Python and SciPy. There are options for NumPy and hd5f as well. Another option is to write your own reader for the .mat format in whatever language you need. Here is the link to the mat file format definition.