The first one is easier to do, but the second one should be checked first to see if it is written correctly. This structure is similar to a JSON object but not, so it is not easy to do.
The first method

include '....'; // 此处为文件名 // 下面只是示例，随便怎么操作$config['hello'] foreach($config['hello'] as $key => $value) { ... } $output = "$config['hello'] = " . var_export($config['hello'], TRUE); file_put_contents('....', $output); // 省略号处为原来的文件名

Mainly usevar_exportto output an array that can be read by PHP. When the second parameter of this function isfalse, it will be output directly. When it istrue, the result will be returned to the variable.
One thing that needs to be reminded is that the array layout generated by this function is not very good-looking. If you mind, just write one yourself.

Update

Modify the example code ofk1

include '....'; $config['hello']['k1'] = 'aaaa'; $output = "$config['hello'] = " . var_export($config['hello'], TRUE); file_put_contents('....', $output);

In fact, the easiest way is not to write the config file like this. The config file format is generally as follows:

 '111', 'k2' => '222', 'k3' => '333' ];

External files can directly assign the value of the array to a variable by requiring the file, such as

$config = require 'config.php';

It’s easy to get and change values, and it’s also easy to write back to files.