What should I do if it prompts array to string conversion when running php code?

Foreword:

The error array to string conversion occurs because when we write the php script, we use the array as a string.

So under what circumstances will such an error occur?

Scenario 1:

This kind of scenario is relatively rare. Most of them are made by novices, and it is easy to find and solve mistakes. It literally means using the array as a string.
Example:

$arr = array(0, 1, 2);

//错误1，双引号可以解析变量，但是双引号中，就会认为它是字符串。
var_dump("$arr");
//错误2
echo $arr;

In this case, the result will be returned:

PHP Notice: Array to string conversion in /path/test.php on line 5
Array

The solution is to convert the array into a string and then use it: for example, use json_encode($arr);

(Learning video sharing: php video tutorial)

Scenario 2:

This kind of scenario is also relatively rare, and it is difficult to understand just by looking at the prompt Array to string conversion Where is the mistake.

When we use curl and pass parameters through post, when the parameter is a two-dimensional array, this error will be reported, which is very magical.

Example:

$data = array([0], [1], [3]);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_HEADER, FALSE);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POST, 1);

//报错行
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

$result = curl_exec($ch);

The solution to this problem is also very simple

Just use http_build_query() to process the parameters. It is recommended that when using curl, all parameters should be processed with http_build_query.

curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($data));

Related recommendations: php introductory tutorial

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