What is Variable Variable Name in PHP?

What is Variable Variable Name in PHP?

A variable variable name is a variable name that is stored inside another variable. Normally, a variable name is a static string. But sometimes, you want to store a variable name inside another variable to be able to participate in operations.

PHP supports variable variable names with following basic rules:

If the name of the original variable is stored in a different variable, you can use the $$var notation to identify the original variable in your PHP source code.

For example, $varnm = “Abdul”; $$varnm represents the variable $Abdul.

If the name of the original variable can be calculated by an expression, you can use the ${exp} notation to identify the original variable in your PHP source code.

For example, $varnm = “Abdul”; ${$varnm.”_1”} represents the variable $Abdul_1.

Variables with variable names can be assigned with new data like normal variables.

For example, $varnm = “Abdul”; $$varnm = “PHP Script”; assigns “PHP Script” to $Abdul.

Variables with variable names can be used in any operations like normal variables.

For example, $varnm = “Abdul”; $$varnm = “PHP Script”; echo ($$varnm. “ is free”); prints “PHP Script is free”.

If you use an expression as the variable name, the result of the expression will be automatically converted to a string, which will be used as the variable name. With this automatic conversion, anything can be used as a variable name. Even an empty string can be used as a variable name, ${“”} is a perfect variable expression.

Now let’s take an example to confirm some rules mentioned above.

Click here to download example file.