How to use the var_export function, how to use var_export

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How to use the var_export function, how to use var_export_PHP tutorial

Jul 13, 2016 am 10:12 AM

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How to use the var_export function, how to use var_export

var_export() function returns structural information about the variables passed to the function. It is similar to var_dump(), but the difference is The representation returned is valid PHP code. var_export must return legal PHP code. In other words, the code returned by var_export can be directly assigned to a variable as PHP code. And this variable will get the same type of value as var_export. Look at a simple example below:

&lt;?php
	
	$arr = array ( 1 , 2 , array ( "apple" , "banana" , "orange" ));  
	var_export ( $arr );  
	
?&gt;

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Program output:

array (
  0 =&gt; 1,
  1 =&gt; 2,
  2 =&gt; 
  array (
    0 =&gt; 'apple',
    1 =&gt; 'banana',
    2 =&gt; 'orange',
  ),
)

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Note that the above output is legal PHP code. If var_dump() is used, the output is:

array(3) {
  [0]=&gt;
  int(1)
  [1]=&gt;
  int(2)
  [2]=&gt;
  array(3) {
    [0]=&gt;
    string(5) "apple"
    [1]=&gt;
    string(6) "banana"
    [2]=&gt;
    string(6) "orange"
  }
}

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You can return a representation of a variable by setting the second parameter of the function to TRUE.

&lt;?php
	
	$v = 'nowamagic';  
	$rs = var_export ( $v, TRUE );  
	
	echo $rs;
?&gt;

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Program execution result:

'nowamagic'

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Note two points:

var_export() will always retain the structured form to store data.
But please remember: the type of variable value at this time is already a string ($var), and the value inside can no longer be taken out in the form of an array.

In the source code of PHPCMS, you can see that many configuration parameters are recorded in arrays, including their channels, content, etc.

function cache_write($file, $string, $type = 'array')  
{  
    if(is_array($string))  
    {  
        $type = strtolower($type);  
        if($type == 'array')  
        {  
            $string = "&lt;?php\n return ".var_export($string,TRUE).";\n?&gt;";  
        }  
        elseif($type == 'constant')  
        {  
            $data='';  
            foreach($string as $key =&gt; $value) $data .= "define('".strtoupper($key)."','".  
addslashes($value)."');\n";  
            $string = "&lt;?php\n".$data."\n?&gt;";  
        }  
    }  
    $strlen = file_put_contents(PHPCMS_CACHEDIR.$file, $string);  
    chmod(PHPCMS_CACHEDIR.$file, 0777);  
    return $strlen;  
}

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