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exist

Check existence of variable, script, function, folder, or class

Syntax

Description

example

exist name returns the type of name as a number. This list describes the type associated with each value:

  • 0 — name does not exist.

  • 1 — name is a variable in the workspace.

  • 2 — name is a file with extension .m, .mlx, or .mlapp, or name is the name of a file with a non-registered file extension (.mat, .fig, .txt).

  • 3 — name is a MEX-file on your MATLAB® search path.

  • 4 — name is a Simulink® model or library file on your MATLAB search path.

  • 5 — name is a built-in MATLAB function. This does not include classes.

  • 6 — name is a P-code file on your MATLAB search path.

  • 7 — name is a folder.

  • 8 — name is a class. (exist returns 0 for Java classes if you start MATLAB with the -nojvm option.)

MATLAB searches starting at the top of the search path, and moving down until a result is found or the last folder on the path is reached. If more than one name exists in a folder, MATLAB displays the first instance of name, according to the Function Precedence Order. Folders are an exception to the function precedence rules. They have precedence over all types except for variables.

For example, if name matches both a file with a .m extension and a P-code file, then exist returns 6, identifying it as a P-code file. If name matches both a variable and a P-code file, exists returns 1, identifying it as a variable. If name matches both a folder and a MATLAB function, exist returns 7, identifying it as a folder.

example

exist name searchType returns the type of name, restricting results to the specified type, searchType. If name of type searchType does not exist, MATLAB returns 0.

example

A = exist(___) returns the type of name to A.

Examples

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Create a variable named testresults, and then confirm its existence in the workspace.

testresults = magic(5);
exist testresults
ans =

     1

A variable named testresults exists in the workspace.

Create the folder myfolder, and then check its existence as a folder.

mkdir myfolder;
exist myfolder dir
ans =

     7

If you specify the type as file, MATLAB® searches for both files and folders, therefore returning the same result.

exist myfolder file
ans =

     7

Check whether the plot function is a built-in function or a file.

A = exist('plot')
A =

     5

This indicates that plot is a built-in MATLAB function.

Input Arguments

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Name of variable, script, function, folder, or class, specified as a character vector. name can include a partial path, but must be in a folder on the search path, or in the current folder. Otherwise, name must include a full path.

If name specifies a file with a non-registered file extension (.mat, .fig, .txt), include the extension. You can also include an extension to prevent conflict with other similar file names. For example, exist file.text.

name is case insensitive on Windows® systems, and case sensitive for files and folder on UNIX® systems.

    Note:   MATLAB does not examine the contents or internal structure of a file and relies solely on the file extension for classification.

Type of results to search for, specified as one of these values:

searchTypeDescriptionPossible Return Values

builtin

Checks only for built-in functions.

5, 0

class

Checks only for classes.

8, 0

dir

Checks only for folders.

7, 0

file

Checks only for files or folders.

2, 3, 4, 6, 7, 0

var

Checks only for variables.

1, 0

See Also

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Introduced before R2006a

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