Variables and functions are utilised in JMeter, just as they are in any other programming language, to make scripts reusable (since a function can be called again and again without having the need to write the same code again and again). Variables can be used to hold any value and then referenced anywhere in your code, just like any other programming language. So, with JMeter, it may be your server name, path, port number, or whatever else you want to save in a variable and utilise in multiple places afterwards.
JMeter has a number of built-in routines that can be used to test various situations. If you're accessing an application on your machine IP rather than an external URL, for example, you can use the machine IP function to get your IP address. JMeter's Function Dialogue may be found in the settings menu, where you can examine the definition and function string.
The syntax for calling a variable and function in your script is shown below :
Variable – {varName}.
Here, varName denotes the name of the variable.
Example – {name}
Function – {_functionName}.
Here, functionName denotes the name of the function.
Example – {_counter()}, {_threadNum} etc.
