php变量作用域 [英] php variable scope

问题描述

我对 php 变量范围感到困惑.例如:

i'm confused about the php variable scope. such as:

while(true){
    $var = "yes , it is a test!";
  }
  printf($var)

$var 是在 while 语句范围内定义的，我们怎么才能让它超出它的范围呢?我在文档上找不到解释.

the $var is defined in while statement scope , how could we get it outside it's scope ? and i can't find explanation on the document .

我想知道 php 如何处理它的范围.

i wonder how php deal with it's scope .

推荐答案

如果你做了 while(true) 你就不会离开 while，所以没关系.但是如果你有一个真实的表达，像这样(这是一个无用的例子，我知道)

If you do while(true) you will not get out of the while, so it wouldn't matter. But if you would have a real expression, something like this (this is a useless example, i know)

$i=0
while($i<10){ 
   $var = "yes , it is a test!"; 
   $i++;
 } 
 printf($var);

会起作用.没有特殊的while"变量范围，printf 将打印您的字符串.检查:http://php.net/manual/en/language.variables.scope.php

Will just work. There is no special "while" variable scope, the printf will print your string. check : http://php.net/manual/en/language.variables.scope.php

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