Name of file, specified as a character vector or string. If you do not specify filename, the load function searches for a file named matlab.mat. Filename can include a file extension and a full or partial path. If filename has no extension (that is, no text after a period), load looks for a file named filename.mat. If filename has an extension other than.mat, the load function treats the file as ASCII data.
When using the command form of load, it is unnecessary to enclose the input in single or double quotes. However, if filename contains a space, you must enclose the argument in single quotes. For example, load 'filename withspace.mat'. ASCII files must contain a rectangular table of numbers, with an equal number of elements in each row. The file delimiter (the character between elements in each row) can be a blank, comma, semicolon, or tab character. The file can contain MATLAB comments (lines that begin with a percent sign,%). Example: 'myFile.mat' Data Types: char string.
Form of variables Input Variables to Load var1.,varN Load the listed variables, specified as individual character vectors or strings. Use the '.' wildcard to match patterns. For example, load('filename.mat','A.' ) or load filename.mat A. loads all variables in the file whose names start with A.
'-regexp', expr1.,exprN Load only the variables or fields whose names match the, specified as character vectors or strings. For example, load('filename.mat','-regexp','^Mon','^Tues') or load filename.mat -regexp ^Mon ^Tues loads only the variables in the file whose names begin with Mon or Tues. Data Types: char string. Use load only when generating MEX functions or code for Simulink ® simulation.
To load compile-time constants, use coder.load. Does not support use of the function without assignment to a structure or array. For example, use S = load(filename), not load(filename). The output S must be the name of a structure or array without any subscripting. For example, S(i) = load('myFile.mat') is not supported. Arguments to load must be compile-time constant character vectors. Does not support loading objects.
If the MAT-file contains unsupported constructs, use S = load(filename,variables) to load only the supported constructs. In a function intended for code generation, the use of save or the use of coder.extrinsic with save is not supported. To save the workspace data to a MAT-file, use the save function prior to generating code. When using the load function to load variables whose size can change at run time, you must explicitly declare the variables as variable-size data by using coder.varsize.
I want to open and read a.raw image in MATLAB. My file can be. I have tried the following three code snippets, but neither gives the expected results. Code Snippet #1 row=576; col=768; fin=fopen('m-001-1.raw','r'); I=fread(fin,row.col,'uint8=uint8'); Z=reshape(I,row,col); Z=Z'; k=imshow(Z); It shows this picture: Code Snippet #2 f=fopen('m-001-1.raw'); a=fread(f); inputimg = reshape(a,768, 576, 3); inputimg = imrotate(inputimg, -90); imwrite(inputimg, 'm-001-1.jpg'); This saves a blank (just white) image in.jpg format. Code Snippet #3 id = fopen('m-001-1.raw', 'r'); x = fread(id, 576,768, 'short'); When I use imshow(x), this picture shows: How do I read this picture correctly? Peter's code (thanks btw!) works assuming that your image is grayscale. For colour images, what you need to do is read in all of the bytes as a single 1D array as we can't use fread to read the data is in as a 3D matrix (at least not to my knowledge.).
After, we then reshape it so that it becomes a 3D matrix. After we reshape the matrix, notice that this is the transposed result. As such, we will have to either transpose each channel independently, or you can cleverly combine and to do the 3D transpose for us. I would rotate the image so that it's 90 degrees clockwise, but this would make the image mirror reflected across the columns. I then use flipdim with the second parameter as 2 as I want to mirror reflect across the columns to get the original image back.
As such, what you would actually have to do is this: row=576; col=768; fin=fopen('m-001-1.raw','r'); I=fread(fin, col.row.3,'uint8=uint8');%// Read in as a single byte stream I = reshape(I, col row 3);%// Reshape so that it's a 3D matrix - Note that this is column major Ifinal = flipdim(imrotate(I, -90),2);% // The clever transpose imshow(Ifinal); fclose(fin);%// Close the file What I get is this image: Alternatively, you can certainly use Peter's code, but you would use it so that you would reconstruct the image one colour plane at a time. In other words, you can do this: row=576; col=768; fin=fopen('m-001-1.raw','r'); I1=fread(fin, col row,'uint8=uint8');%// Red channel I2=fread(fin, col row,'uint8=uint8');%// Green channel I3=fread(fin, col row,'uint8=uint8');%// Blue channel I1 = I1.' ;%// Transpose each channel separately Ifinal = cat(3, I1, I2, I3);%// Create 3D matrix imshow(Ifinal); fclose(fin); You'll get exactly the same image as above. Your row/col sizes are reversed. Since MATLAB arrays are column-major, and raster images are usually stored row-major, you need to read the image as a col row matrix, then transpose it.
Row=576; col=768; fin=fopen('m-001-1.raw','r'); I=fread(fin, col row,'uint8=uint8'); Z=I'; k=imshow(Z) The image replication is happening because you're short 768-576 = 192 pixels per line, so each line is progressively off that amount. After 4 lines, you've made up the difference (4.192 = 768), so you have a 4-image replication.
Operator Action Taken%. k Skip the field. K is any conversion specifier identifying the field to skip. Textscan does not create an output cell for any such fields.
Example: '%s%.s%s%s%.s%.s%s' (spaces are optional) converts the text 'Blackbird singing in the dead of night' into four output cells with 'Blackbird' 'in' 'the' 'night' '%. ns' Skip up to n characters, where n is an integer less than or equal to the number of characters in the field.
Example: '%.3s%s' converts 'abcdefg' to 'defg'. When the delimiter is a comma, the same delimiter converts 'abcde,fghijkl' to a cell array containing 'de';'ijkl'. '%. nc' Skip n characters, including delimiter characters.
Field Width textscan reads the number of characters or digits specified by the field width or precision, or up to the first delimiter, whichever comes first. A decimal point, sign ( + or -), exponent character, and digits in the numeric exponent are counted as characters and digits within the field width. For complex numbers, the field width refers to the individual widths of the real part and the imaginary part. For the imaginary part, the field width includes + or − but not i or j. Specify the field width by inserting a number after the percent character (%) in the conversion specifier.
Example:%5f reads '123.456' as 123.4. Example:%5c reads 'abcdefg' as 'abcde'. When the field width operator is used with single characters (%c), textscan also reads delimiter, white-space, and end-of-line characters. Example:%7c reads 7 characters, including white-space, so 'Day and night' reads as 'Day and'. Precision For floating-point numbers (%n,%f,%f32,%f64), you can specify the number of decimal digits to read.
Example:%7.2f reads '123.456' as 123.45. Literal Text to Ignore textscan ignores the text appended to the formatSpec conversion specifier. Example: Level%u8 reads 'Level1' as 1.
Sscanf
Example:%u8Step reads '2Step' as 2. Data Types: char string. Locale for reading dates, specified as the comma-separated pair consisting of 'DateLocale' and a character vector in the form xx YY, where xx is a lowercase ISO 639-1 two-letter code that specifies a language, and YY is an uppercase ISO 3166-1 alpha-2 code that specifies a country. For a list of common values for the locale, see the Locale name-value pair argument for the function.
Use DateLocale to specify the locale in which textscan should interpret month and day of week names and abbreviations when reading text as dates using the%D format specifier. Example: 'DateLocale','jaJP'. End-of-line characters, specified as the comma-separated pair consisting of 'EndOfLine' and a character vector or string. The character vector must be ' r n' or it must specify a single character. Common end-of-line characters are a newline character ( ' n') or a carriage return ( ' r'). If you specify ' r n', then the importing function treats any of r, n, and the combination of the two ( r n) as end-of-line characters.
The default end-of-line sequence is n, r, or r n, depending on the contents of your file. If there are missing values and an end-of-line sequence at the end of the last line in a file, then the importing function returns empty values for those fields. This ensures that individual cells in output cell array, C, are the same size. Example: 'EndOfLine',':' Example: 'EndOfLine',':' Data Types: char string. File or text data, returned as a cell array. For each numeric conversion specifier in formatSpec, the textscan function returns a K-by-1 MATLAB numeric vector to the output cell array, C, where K is the number of times that textscan finds a field matching the specifier. For each text conversion specifier (%s,%q, or%.) in formatSpec, the textscan function returns a K-by-1 cell array of character vectors, where K is the number of times that textscan finds a field matching the specifier.
For each character conversion that includes a field width operator, textscan returns a K-by- M character array, where M is the field width. For each datetime or categorical conversion specifier in formatSpec, the textscan function returns a K-by-1 datetime or categorical vector to the output cell array, C, where K is the number of times that textscan finds a field matching the specifier. Algorithms textscan converts numeric fields to the specified output type according to MATLAB rules regarding overflow, truncation, and the use of NaN, Inf, and -Inf. For example, MATLAB represents an integer NaN as zero. If textscan finds an empty field associated with an integer format specifier (such as%d or%u), it returns the empty value as zero and not NaN.
When matching data to a text conversion specifier, textscan reads until it finds a delimiter or an end-of-line character. When matching data to a numeric conversion specifier, textscan reads until it finds a nonnumeric character.
When textscan can no longer match the data to a particular conversion specifier, it attempts to match the data to the next conversion specifier in the formatSpec. Sign ( + or -), exponent characters, and decimal points are considered numeric characters. Sign Digits Decimal Point Digits Exponent Character Sign Digits Read one sign character if it exists. Read one or more digits.
Read one decimal point if it exists. If there is a decimal point, read one or more digits that immediately follow it.
Read one exponent character if it exists. If there is an exponent character, read one sign character. If there is an exponent character, read one or more digits that follow it. Textscan imports any complex number as a whole into a complex numeric field, converting the real and imaginary parts to the specified numeric type (such as%d or%f). Valid forms for a complex number are. Cks serial episode 100 always and forever.
So I've been trying to read this particular.mat file into R. I don't know too much about matlab, but I know enough that the R.matlab package can only read uncompressed data into R, and to save it as uncompressed I need to save it as such in matlab by using save new.mat -v6. Okay, so I did that, but when I used readMat('new.mat') in R, it just got stuck loading that forever. I also tried using package hdf5 via: hdf5load('new.mat', load=FALSE)-g Error in hdf5load('new.mat', load = FALSE): can't handle hdf type 201331051 I'm not sure what this problem could be, but if anyone wants to try to figure this out the file is located at and is called inventory.mat (the first file).
Thanks for your help! This particular file has one object, inventory, which is a struct object, with a lot of different things inside of it.
Some are cell arrays, others are vectors of doubles or logicals, and a couple are matrices of doubles. It looks like R.matlab does not like cells arrays within structs, but I'm not sure what's causing issues for R to load this. For reasons like this, I'd generally recommend avoiding mapping structs in Matlab to objects in R. It is similar to a list, and this one can be transformed to a list, but it's not always a good idea. I recommend creating a new file, one for each object, e.g. Ids = inventory.instanceids and save each object to either a separate.mat file, or save all of them, except for the inventory object, into 1 file. Even better is to go to text, e.g via csvwrite, so that you can see what's being created.
Read Matlab Files
I realize that's going around use of a Matlab to R reader, but having things in a common, universal format is much more useful for reproducibility than to acquire a bunch of different readers for a proprietary format. Alternatively, you can pass objects in memory via R.matlab, or + the R/DCOM interface (on Windows). Although this doesn't address how to use R.matlab, I've done a lot of transferring of data between R and Matlab, in both directions, and I find that it's best to avoid.mat files (and, similarly,.rdat files). I like to pass objects in memory, so that I can inspect them on each side, or via standard text files.
Textscan![]()
Dealing with application specific file formats, especially those that change quite a bit and are inefficient (I'm looking at you MathWorks), is not a good use of time. I appreciate the folks who work on readers, but having a lot more control over the data structures used in the target language is very much worth the space overhead of using a simple output file format. In-memory data transfer is very nice because you can interface programs, but that may be a distraction if your only goal is to move data.
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