mustBeFile

Validate that path refers to file

Since R2020b

Syntax

mustBeFile(path)

Description

mustBeFile(path) throws an error if path does not refer to a file. This function does not return a value.

mustBeFile calls the following function to determine if the input is file:

• isfile

Examples

Ensure Input Is a Valid File Name

Use the mustBeFile function to ensure that a file path passed to a function is valid.

The readLine function ensures that the file path is valid before accessing the file.

function r = readLine(path)
    arguments
        path {mustBeFile}
    end
    fid = fopen(path);
    r = fgetl(fid);
    fclose(fid)
end

Passing this path to a folder to the readLine function results in an error.

r = readLine("C:\Users\Public")

Error using readLine (line 3)
 r = readLine("C:\Users\Public")
              ^^^^^^^^^^^^^^^^^
Invalid argument at position 1. These files do not exist: 'C:\Users\Public'.

Input Arguments

path — Path to file

string scalar | character vector

Path to a file, specified as the fully qualified file name, including folders containing the file from the context in which the function executes.

Example: "H:\myfolder\myfile.txt"

Data Types: char | string

Tips

• mustBeFile is designed to be used for property and function argument validation.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Version History

Introduced in R2020b