isenv

Determine if environment variable exists

Syntax

tf = isenv(name)

Description

tf = isenv(name) returns logical 1 (true) if name is an operating system environment variable. If name does not exist, then isenv returns logical 0 (false).

On most UNIX^® platforms, an environment variable can exist with an empty value (""). On the Microsoft^® Windows^® platform, setting the value of an environment variable to "" is equivalent to removing the variable.

Examples

Create and Test Environment Variable

Create environment variable myVar and check that it exists.

setenv("myVar","myValue");
isenv("myVar")

ans = logical
   1

Remove myVar and check that it no longer exists.

unsetenv("myVar");
isenv("myVar")

ans = logical
   0

Input Arguments

name — Environment variable name

string scalar | character vector

Environment variable name, specified as a string scalar or character vector.

Example: "PATH"

Version History

Introduced in R2022b