Using explode function with a variable in the string? - php

Question

I have an array with $post_id as keys. When save the $data, I saved it as a string:
foreach( $data as $post_id => $details )
$string .= "-pid-$post_id-$details";
When use the data, I need to convert it back to array with $post_id as key and $details as value. How to explode it when I don't know what is the $post_id ?

Answer 1

Don't do it this way. if you need to serialize a string use json_encode():
$string = json_encode($data);
Then, when you need to decode it again:
$data = json_decode($string);
Safe and easy.
Here's the PHP reference: json_encode()

Answer 2

php has a method called serialize which will take an array (such as $_POST) and convert it to a string that can then be recreated into an array with unserialize
<?php
// $_POST looks like this for example:
// $_POST['value'] = 100;
$string = serialize($_POST);
echo $string; // Prints '"a":1:{s:5:"value";s:3:"100";}'
$data = unserialze($string);
print_r($data); // Prints Array[0] ( 'value' => '100' )
?>
I won't lecture about not sanitizing user input, but SANITIZE USER INPUT.
serialize
unserialize
Note that this is a binary string which may include null bytes, and needs to be stored and handled as such. For example, serialize() output should generally be stored in a BLOB field in a database, rather than a CHAR or TEXT field. -- from php docs

Answer 3

You would need to explode the string using
explode ( string $delimiter , string $string [, int $limit ] )
This will return your data as an array
for example
foreach($data AS $post_id => $details) {
$string .= "|||$post_id||$details"
}
then to get your data back out of string
$newArray = explode('|||', $string);
foreach($newArray AS $key=>$val){
$holding = explode('||', $val);
$finalArray[$holding[0]] = $val;
}
Now you will have an array with key being the id and val being the details for each of the items in the string.
EDIT:
Or use serialize and unserialize like Brombomb suggested.

Answer 4

If I understand your question...
$temp = explode('-pid-', $string);
array_shift($temp);
foreach ($temp as $item) {
list($post_id, $value) = explode('-', $item);
$data[$post_id] = $value;
}
json_encode and associated json_decode may be a better option for "stringifying" your data in the first place. However, there may be a legitimate reason for doing it the way you've chosen to do it.