PHP file operation: how to save array data to a file (two methods)

In the previous article "How to check for null values ​​using PHP (4 methods)", we introduced the method of using PHP to check whether a given value (variable) is null. This time we will talk about data storage in PHP and see how to store array data in a specified file. Interested friends can learn about it~

→Related recommendations: 《php file operation series summary (continuously updated~)》

During the development process, we often use var_dump() to print the array content, but sometimes it is inconvenient for us to view debugging information through the browser. At this time, the information can be output to a file for viewing. Today, this article will introduce to you two methods of writing array data to files.

Method 1: Use the var_export() function

var_export - Output or return the parsable string representation of the variable

Syntax: var_export(mixed $value, bool $return = false)

• value: The variable name you want to output.

• return: When this parameter is true, var_export() will return a variable instead of outputting it.

This function returns structural information about the variables passed to the function. It is similar to var_dump(), except that the representation returned is legal PHP code. We can return a representation of a variable by setting the second parameter of the function to TRUE.

Let’s use the following example to see how to use the var_export() function to save array data into a file

<?php
//$cache的值是更新缓存时从数据库中取出来的
$cache = array(
    &#39;id&#39;            =>  2,
    &#39;name&#39;          =>  &#39;李娜&#39;, 
    &#39;age&#39;           =>  23,
    &#39;sex&#39;           =>  &#39;女&#39;,
    &#39;college&#39;       =>  "软件技术",
    &#39;subject&#39;       =>  "PHP编程"
); 

//将数据写入缓存文件
$content = "<?php\nreturn ".var_export($cache,true)."\n?>";    //这里使用var_export()
file_put_contents(&#39;./cache.php&#39;, $content);
?>

Analysis code:

• ##Utilization

  var_export($cache,true)Return the parsable string of the array variable

• ##$content = "";

  Concatenate the strings and assign the value to the variable $content;

• file_put_contents('./cache.php' , $content)

  Write data$content in the cache.php file. The file_put_contents() function can write a string into a file. For details, you can read the article "

  php file operation: how to clear the file and re-add data

  ".

So in cache.php, which was an empty file at the beginning, the current content is:

Call the cache file You only need to use require() to copy the contents of the cache file to a variable, and then output the array variable:

<?php
$cache = require(&#39;./cache.php&#39;);
var_dump($cache);
?>

The output result is:

Method 2: Use the serialize methodUse serialize to serialize the array and store it in the file; when calling, use unserialize to restore it.

Let’s use the following example to see how to use the serialize() function to store array data into a file

<?php
$file=&#39;./cache.php&#39;; 
$cache = array(
    &#39;id&#39;            =>  2,
    &#39;name&#39;          =>  &#39;李娜&#39;, 
    &#39;age&#39;           =>  23,
    &#39;sex&#39;           =>  &#39;女&#39;,
    &#39;college&#39;       =>  "软件技术",
    &#39;subject&#39;       =>  "PHP编程"
); 
//缓存 
if(false!==fopen($file,&#39;w+&#39;)){ 
  file_put_contents($file,serialize($cache));//写入缓存 
} 
?>

Use

Store the serialized array data in the cache.php file. Therefore, in cache.php, which was an empty file at the beginning, the current content is:

When reading the cache, you need to use unserialize to restore the data in cache.php

<?php
//读出缓存 
$file=&#39;./cache.php&#39;; 
$handle=fopen($file,&#39;r&#39;); 
$cache=unserialize(fread($handle,filesize($file))); 
var_dump($cache);
?>

The output result is:

Okay, that’s all. If you want to know anything else, you can click this. → →

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