如何在PHP中创建一个取消指定变量的函数

问题描述：

I'm trying to make a function that takes a variable whether it was set or not,

like the function isset()

//we have this array
$array  = array();
isset($array["test"]);//this one is valid 
myFunc($array["test"]);//this one is not valid

how can i let my function take not set variables?

我正在尝试创建一个带变量的函数，无论它是否已设置， p> \ n

就像函数isset（） p>

  //我们有这个数组
 $ array = array（）; 
isset（$ array [“test”  ]）; //这个有效
myFunc（$ array [“test”]）; //这个无效
  code>  pre> 
 
 我怎么能让我的 函数取不设置变量？   p> 
  div>

答

Pass the argument as a reference http://php.net/manual/en/language.references.pass.php

function myFunc(&$val)
{
    return isset($val);
}

var_dump(myFunc($undefined));

答

It's common to come across this problem if you're using $_GET and friends, because you can't rely on a given field being passed into your program.

I use a utility class for this, so I can avoid errors with unset vars and also populate defaults into them.

<?php
function defArrayElem(&$array, $key, $default=null) {
    if(!isset($array[$key])) {$array[$key]=$default;}
}

//repeat for all the $_GET/$_POST vars you expect...
defArrayElem($_GET,'keyname','default-value');
?>

Now you don't need to worry about checking if they're set or not.

如何在PHP中创建一个取消指定变量的函数

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