MATLAB: How to ensure that all the numbers use the same number of characters when converting from unicode to the native format in MATLAB 7.9 (R2009b)

MATLAB

I am converting an array of numbers from unicode to the native format using:

x = [4 87 44 9987];
u = unicode2native(num2str(x));

The length of the resulting array, 'u', depends on the input numbers. I would like to specify a fixed number of characters for all the elements of the array.

Best Answer

In order to specify a fixed number of characters to be used for all characters in the array, use the SPRINTF function with a syntax similar to:

x = [4 87 44 9987];
str = sprintf('% 8d',x)
u = unicode2native(str)

In this example, each element of the resulting string will contain 8 characters, padded with spaces (ASCII character 32).

Related Solutions

MATLAB: How to convert an array of binary values into the corresponding decimal number within MATLAB

You can convert the array to a decimal number by first converting it into a binary string, then using the BIN2DEC function to convert the string into a number:

x = [1 0 0 0 0 0 0 0];
% convert x to a string array
str_x = num2str(x);
% remove the spaces in the string, so it 
% becomes '10000000'
str_x(isspace(str_x)) = '';
% now use BIN2DEC to convert the binary 
% string to a decimal number
y = bin2dec(str_x);

For MATLAB 7.0 (R14) and releases after that, BIN2DEC ignores any space (' ')

characters in the input string. Hence, the following step is not required in the above code:

str_x(isspace(str_x)) = '';

Please note that the BIN2DEC function works with strings of size less than 52 bits.

To convert a binary string with more than 52 bits, you would need to use the symbolic Math Toolbox in MATLAB.

For example, a binary string can be converted using the text2int function in MATLAB 7.8 (R2009a).

z = evalin(symengine,'text2int("1111000101111100010111110001011111000001011111000101010",2)')

MATLAB: Working with unicode paths

As others have alluded to, the problem seems to be with Matlab touching the character data. I still don't have a solution for changing the directory, since I don't know of a way of doing this without using Matlab strings.

Here's how to read a file (in this case to bytes) using Java which bypasses the unicode problem.

dir_obj    = java.io.File(DIR_ROOT);
dir_files  = dir_obj.listFiles;
file_bytes = typecast(org.apache.commons.io.FileUtils.readFileToByteArray(dir_files(end)),'uint8');

NOTE: There are other methods of extracting bytes given a file but the method alluded to above exists on my system and seemed the most straightforward.

Found from: http://stackoverflow.com/questions/6058003/elegant-way-to-read-file-into-byte-array-in-java

At this point native2unicode() or char() would be fine if you wanted the content as a string.

It seems like the problem is most likely tied to combining characters, which is one way of adding something like an accent to a "normal" letter.

http://en.wikipedia.org/wiki/Combining_character

I believe that the file on disk which has caused the problem actually consists of a combined character which adds an accent to an e, thus the 101 769, which is the letter e followed by a combining acute accent:

http://www.fileformat.info/info/unicode/char/301/index.htm

Best Answer

Related Solutions

MATLAB: How to convert an array of binary values into the corresponding decimal number within MATLAB

MATLAB: Working with unicode paths

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