open (MATLAB Functions)

Open files based on extension

Syntax

```
open('name')
```

Description

open('name') opens the object specified by the string name. The specific action taken upon opening depends on the type of object specified by name.

name
Action

Variable
Open array name in the Array Editor (the array must be numeric).

M-file (name.m)
Open M-file name in M-file Editor.

Model (name.mdl)
Open model name in Simulink.

MAT-file (name.mat)
Open MAT-file and store variables in a structure in the workspace.

Figure file (*.fig)
Open figure in a figure window.

P-file (name.p)
Open the corresponding M-file, name.m, if it exists, in the M-file Editor.

HTML file (*.html)
Open HTML document in Help browser.

PDF file (*.pdf)
Open PDF document in Adobe Acrobat.

Other extensions (name.xxx)
Open name.xxx by calling the helper function openxxx, where openxxx is a user-defined function.

No extension (name)
Open name in the default editor. If name does not exist, then open checks to see if name.mdl or name.m is on the path or in the current directory and, if so, opens the file returned by which('name').

name	Action
Variable	Open array `name` in the Array Editor (the array must be numeric).
M-file (`name.m)`	Open M-file `name` in M-file Editor.
Model (`name.mdl`)	Open model `name` in Simulink.
MAT-file (`name.mat`)	Open MAT-file and store variables in a structure in the workspace.
Figure file (`*.fig`)	Open figure in a figure window.
P-file (`name.p`)	Open the corresponding M-file, `name.m`, if it exists, in the M-file Editor.
HTML file (`*.html`)	Open HTML document in Help browser.
PDF file (`*.pdf`)	Open PDF document in Adobe Acrobat.
Other extensions (`name.xxx`)	Open `name.xxx` by calling the helper function `openxxx`, where `openxxx` is a user-defined function.
No extension (`name`)	Open `name` in the default editor. If `name` does not exist, then `open` checks to see if `name.mdl` or `name.m` is on the path or in the current directory and, if so, opens the file returned by `which('name')`.

If more than one file with the specified filename name exists on the MATLAB path, then open opens the file returned by which('name').

If no such file name exists, then open displays an error message.

You can create your own openxxx functions to set up handlers for new file types. open('filename.xxx') calls the openxxx function it finds on the path. For example, create a function openlog if you want a handler for opening files with file extension .log.

Examples

Example 1 -- Opening a File on the Path

To open the M-file copyfile.m, type

```
open copyfile.m
```

MATLAB opens the copyfile.m file that resides in toolbox\matlab\general. If you have a copyfile.m file in a directory that is before toolbox\matlab\general on the MATLAB path, then open opens that file instead.

Example 2 -- Opening a File Not on the Path

To open a file that is not on the MATLAB path, enter the complete file specification. If no such file is found, then MATLAB displays an error message.

```
open('D:\temp\data.mat')
```

Example 3 -- Specifying a File Without a File Extension

When you specify a file without including its file extension, MATLAB determines which file to open for you. It does this by calling

```
 which('filename')
```

In this example, open matrixdemos could open either an M-file or a Simulink model of the same name, since both exist on the path.

dir matrixdemos.*

  matrixdemos.m    matrixdemos.mdl

Because the call which('matrixdemos') returns the name of the Simulink model, open opens the matrixdemos model rather than the M-file of that name.

open matrixdemos          % Opens model matrixdemos.mdl

Example 4 -- Opening a MAT-File

This example opens a MAT-file containing MATLAB data and then keeps just one of the variables from that file. The others are overwritten when ans is reused by MATLAB.

% Open a MAT-file containing miscellaneous data.
open D:\temp\data.mat

ans = 

          x: [3x2x2 double]
          y: {4x5 cell}
          k: 8
    spArray: [5x5 double]
   dblArray: [4x1 java.lang.Double[][]]
   strArray: {2x5 cell}
   

% Keep the dblArray value by assigning it to a variable.
dbl = ans.dblArray
 
dbl =
 
java.lang.Double[][]:
    [ 5.7200]    [ 6.7200]    [ 7.7200]
    [10.4400]    [11.4400]    [12.4400]
    [15.1600]    [16.1600]    [17.1600]
    [19.8800]    [20.8800]    [21.8800]

Example 5 -- Using a User-Defined Handler Function

If you create an M-file function called opencht to handle files with extension .cht, and then issue the command

```
open myfigure.cht
```

open calls your handler function with the following syntax:

```
opencht('myfigure.cht')
```

See Also

edit, load, save, saveas, uiopen, which, file_formats, path

ones openfig