How do I store an array in a file to access as an array later with PHP?

If you don't need the dump file to be human-readable, you can just serialize() the array.

storing:

file_put_contents('yourfile.bin', serialize($array));

retrieving:

$array = unserialize(file_get_contents('yourfile.bin'));

Use serialize and unserialize

// storing
$file = '/tmp/out.data';
file_put_contents($file, serialize($mydata)); // $mydata is the response from your remote API

// retreiving
$var = unserialize(file_get_contents($file));

Or another, hacky way:

var_export() does exactly what you want, it will take any kind of variable, and store it in a representation that the PHP parser can read back. You can combine it with file_put_contents to store it on disk, and use file_get_contents and eval to read it back.

// storing
$file = '/tmp/out.php';
file_put_contents($file, var_export($var, true));

// retrieving
eval('$myvar = ' . file_get_contents($file) . ';');

Another fast way not mentioned here:

That way add header with <?php start tag, name of variable \$my_array = with escaped \$ and footer ?> end tag.

Now can use include() like any other valid php script.

<?php
  // storing
  $file = '/tmp/out.php';
  $var = ['a'=>1,'b'=>2,'c'=>3,'d'=>4,'e'=>5];

  file_put_contents($file,
    "<?php\n\$my_array = "
      .var_export($var, true)
    .";\n?>"
  );

  // retrieving as included script
  include($file);

  //testing
  print_r($my_array);
?>

out.php will look like this

<?php
  $my_array = array (
    'a'=>1,
    'b'=>2,
    'c'=>3,
    'd'=>4,
    'e'=>5
  );
?>

Talking about php use, for performance sake, avoid encoding and decoding everything, just save array with:

file_put_contents('dic.php', "<?php return " . var_export($dic, true) . ";\n");

and call normally with

$dic = include "dic.php";

Reference: https://php.net/include

You can use serialize to make it into a string to write to file, and the accompanying unserialize to return it to an array structure.

I'd suggest using a language independent structure though, such as JSON. This will allow you to load the files using different languages than PHP, in case there's a chance of that later. json_encode to store it and json_decode($str, true) to return it.

Use php's serialze:

file_put_contents("myFile",serialize($myArray));

This is an easy way to write one var to one file. Basically, you're creating a valid php file, to store and then including it, to retrieve.

// arraywritetofile('file.php','myvarName', array('pets'=>array('cow'=>'bessie','dog'=>'fido'));
 // thefile = path to file you want to write, $varname is the name your written file will have, $ra is the actual ra you are writing.
 // to read, just go include 'file.php'; and your $myvarName will be in the scope.
    function arraywritetofile($thefile, $varname, $ra){
        $ra    = var_export($ra, true);
        $write = '<?php
            $'.$varname.' =
            '.$ra.';
            ?>';
        
        $put = file_put_contents($thefile, $write);
        //echo "<pre>".htmlentities($write)."</pre>";
        
    }//  func

Use serialize and unserialize

$data = ["name" => "John", "age" => 30, "city" => "New York"];
$file = '/data_folder/data.txt';

// save data
file_put_contents($file, serialize($data));
//a:3:{s:4:"name";s:4:"John";s:3:"age";i:30;s:4:"city";s:8:"New York";} 

// get data
$data = unserialize(file_get_contents($file));

Serialize:

• Format: Outputs a specialized serialized format.
• Use Case: Commonly used in PHP to serialize complex data structures (arrays, objects) for storage in a file or a database.
• Data Types: Supports a wider range of data types compared to JSON, including objects, resources, and more.
• Readability: Serialized data is not human-readable, and it's generally meant to be used within PHP applications.

Serialize vs. Json

• If you need to exchange data between different programming languages or platforms, JSON is a more universal choice.

• If the data is only meant to be used within a PHP application and you need to preserve the exact state of objects, serialize might be more suitable.

• JSON is often preferred for data interchange due to its simplicity, readability, and widespread support.

Choose between json_encode and serialize based on your specific use case and the requirements of your application.

json_encode:

$data = ["name" => "John", "age" => 30, "city" => "New York"];
$file = '/data_folder/data.txt';

// save data
file_put_contents($file,json_encode($data));
// {"name":"John","age":30,"city":"New York"}

// get data
$data = json_decode(file_get_contents('$file'), true);

• Format: Outputs data in JSON format.
• Use Case: Primarily used for encoding data to be sent between a server and a web application, or for storing configuration settings.
• Data Types: Supports a limited set of data types: strings, numbers, arrays, objects, booleans, and null.
• Readability: JSON is human-readable and widely supported by various programming languages.

Using json_encode/decode changes the array to an object.

So use serialize/unserialize instead.

// Define file path
$file = 'filename.php';

// Store array to a file
file_put_contents($file, serialize($array));

// Retrieve array from a file
$array = unserialize(file_get_contents($file));

I made a tiny library (~2 KB; <100 lines) that allows you to do just this: varDx

It has functions to write, read, modify, check and delete data. It implements serialization, and therefore supports all data types.

Here's how you can use it:

<?php
require 'varDx.php';
$dx = new \varDx\cDX; //create an object
$dx->def('file.dat'); //define data file

$val1 = "this is a string";
$dx->write('data1', $val1); //writes key to file
echo $dx->read('data1'); //returns key value from file

In your specific case:

$array1 = array(
    "foo" => "bar",
    "bar" => "foo",
);

//writing the array to file
$dx->write('myarray', $array1);

//reading array from file
$array2 = $dx->read('myarray')

//modifying array in file after making changes
$dx->write('myarray', $array2);