MATLAB Function Reference

load

Load workspace variables from disk

Syntax

• load
  load('filename')
  load('filename', 'X', 'Y', 'Z')
  load('filename', '-regexp', exprlist)
  load('-mat', 'filename')
  load('-ascii', 'filename')
  S = load(...)
  load filename -regexp expr1 expr2 ...
  

Description

load loads all the variables from the MAT-file matlab.mat, if it exists, and returns an error if it doesn't exist.

load('filename') loads all the variables from filename given a full pathname or a MATLABPATH relative partial pathname. If filename has no extension, load looks for a file named filename.mat and treats it as a binary MAT-file. If filename has an extension other than .mat, load treats the file as ASCII data.

load('filename', 'X', 'Y', 'Z') loads just the specified variables from the MAT-file. The wildcard '*' loads variables that match a pattern (MAT-file only).

load('filename', '-regexp', exprlist) loads those variables that match any of the regular expressions in exprlist, where exprlist is a comma-delimited list of quoted regular expressions.

load('-mat', 'filename') forces load to treat the file as a MAT-file, regardless of file extension. If the file is not a MAT-file, load returns an error.

load('-ascii', 'filename') forces load to treat the file as an ASCII file, regardless of file extension. If the file is not numeric text, load returns an error.

S = load(...) returns the contents of a MAT-file in the variable S. If the file is a MAT-file, S is a struct containing fields that match the variables retrieved. When the file contains ASCII data, S is a double-precision array.

load filename -regexp expr1 expr2 ... is the command form of the syntax.

Use the functional form of load, such as load('filename'), when the file name is stored in a string, when an output argument is requested, or if filename contains spaces. To specify a command-line option with this functional form, specify any option as a string argument, including the hyphen. For example,

• load('myfile.dat', '-mat')
  

Remarks

For information on any of the following topics related to saving to MAT-files, see Importing Data from MAT-Files in the "MATLAB Programming" documentation:

• Previewing MAT-file contents
• Loading binary data
• Loading ASCII data

You can also use the Current Directory browser to view the contents of a MAT-file without loading it--see Viewing Information About M-Files and MAT-Files.

Examples

Example 1 -- Loading From a Binary MAT-file

To see what is in the MAT-file prior to loading it, use whos -file:

• whos -file mydata.mat
    Name           Size            Bytes  Class
  
    javArray      10x1                     java.lang.Double[][]
    spArray        5x5                 84  double array (sparse)
    strArray       2x5                678  cell array
    x              3x2x2               96  double array
    y              4x5               1230  cell array
  

Clear the workspace and load it from MAT-file mydata.mat:

• clear
  load mydata
  
  whos
    Name           Size             Bytes  Class
  
    javArray      10x1                     java.lang.Double[][]
    spArray        5x5                 84  double array (sparse)
    strArray       2x5                678  cell array
    x              3x2x2               96  double array
    y              4x5               1230  cell array
  

Example 2 -- Loading From an ASCII File

Create several 4-column matrices and save them to an ASCII file:

• a = magic(4);  b = ones(2, 4) * -5.7;  c = [8 6 4 2];
  save -ascii mydata.dat
  

Clear the workspace and load it from the file mydata.dat. If the filename has an extension other than .mat, MATLAB assumes that it is ASCII:

• clear
  load mydata.dat
  

MATLAB loads all data from the ASCII file, merges it into a single matrix, and assigns the matrix to a variable named after the filename:

• mydata
  mydata =
     16.0000    2.0000    3.0000   13.0000
      5.0000   11.0000   10.0000    8.0000
      9.0000    7.0000    6.0000   12.0000
      4.0000   14.0000   15.0000    1.0000
     -5.7000   -5.7000   -5.7000   -5.7000
     -5.7000   -5.7000   -5.7000   -5.7000
      8.0000    6.0000    4.0000    2.0000
  

Example 3 -- Using Regular Expressions

Using regular expressions, load from MAT-file mydata.mat those variables with names that begin with Mon, Tue, or Wed:

• load('mydata', '-regexp', '^Mon|^Tue|^Wed');
  

Here is another way of doing the same thing. In this case, there are three separate expression arguments:

• load('mydata', '-regexp', '^Mon', '^Tue', '^Wed');
  

See Also

clear, fprintf, fscanf, partialpath, save, spconvert, who

listdlg

loadobj

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