Variable variable, this word is too lofty to explain. Looks very "bigger". It also has a name called a variable.
We think these names are not very scientific. After all, they are all imported things that have been translated.
A variable variable is actually a variable symbol before the declared variable.
Example:
<?php //定义了一个变量叫作 $shu 将$shu这个变量的值设为字符串的biao $shu = 'biao'; //定义了一个【变量】$biao。将他的值设置为鼠标 $biao = '鼠标'; //$$shu 就是可变变量：在已声明的变量$shu前又加上了一个变量符 echo $$shu; ?>
Description of the above process: The value of $shu is 'biao' of the string. I add a $ (dollar sign) before $shu, which can be understood as the following transformation process:
$$shu
${$shu} Divide it into two pieces and look at it
${'biao'} interprets the variable $shu as biao
$biao and $biao is also a variable. The corresponding value is: mouse
You can write several variable variables yourself Just for fun, what is the result of running the following code?
<?php $shu = 'biao'; $biao = 'wo'; $wo = 'test'; $test = 'sina'; $sina = 'zhongguo'; $zhongguo = 'china'; $china = '我爱你'; //别运行，自己去推理一下代码。也写几个可变变量玩玩吧！ echo $$$$$shu; ?>
