How can I convert a string with square brackets into an array? - php

Question

I got this from the name attribute of a field
name="field[a][2][b][0][c][1][field_name]"
after serializing the form, I got this:
array('field[a][2][b][0][c][1][field_name]'=>'value')
and I need to convert that into the following array:
$field = array (
'a' => array (
[2] => array (
'b' => array (
[0] => array (
'c' => array (
[1] => array (
'field_name'=>'value'
)
)
)
)
)
)
);
do I need some sort of foreach function or php can recognize this string as array?

Answer 1

If you want the result nested, use parse_str().
$text = "field[a][2][b][0][c][1][field_name]=value";
parse_str($text, $result);
print_r($result);
Output:
Array
(
[field] => Array
(
[a] => Array
(
[2] => Array
(
[b] => Array
(
[0] => Array
(
[c] => Array
(
[1] => Array
(
[field_name] => value
)
)
)
)
)
)
)
)
See https://3v4l.org/7nmFT

Answer 2

You can get values in brackets with the regular expression, and then reduce it to the array that you want:
$key = 'field[a][2][b][0][c][1][field_name]';
$value = 'value';
$matches = array();
preg_match_all('/\[([^[]+)\]/', $key, $matches);
$keys = array_reverse($matches[1]);
$result = array_reduce($keys, function ($array, $item) {
return array($item => $array);
}, $value);
Explanation
In the regular expression \[([^[]+)\]:
([^[]+) is matches any symbol except opening bracket, one or more
times, and gets it into the capturing group (I hope you will not have nested brackets);
\[...\] is literally matches brackets around.
The preg_match_all function should populate the $matches array with following data:
Array
(
[0] => Array
(
[0] => [a]
[1] => [2]
[2] => [b]
[3] => [0]
[4] => [c]
[5] => [1]
[6] => [field_name]
)
[1] => Array
(
[0] => a
[1] => 2
[2] => b
[3] => 0
[4] => c
[5] => 1
[6] => field_name
)
)
The $matches[0] have values of a full match and the $matches[1] have values of our first and only capturing group. We have interested only in capturing group values.
Then with the array_reduce function we can simply go through keys in the reverse order, and sequentially wrap our value into an array.

Answer 3

You can use explode function to do it. But the values should have space in between them, for example "Hello World" in which the values would be in Array ( [0] => Hello [1] => world ) but in your case it would be like Array ( [0] => field[a][2][b][0][c][1][field_name] ) until $name as space in-between the characters or word.
$name="field[a][2][b][0][c][1][field_name]"
$name_array = explode(" ",$name);
print_r ($name_array);

Answer 4

When testing your problem on my PHP server with this test code
<form method="post">
<input type="text" name="field[a][2][b][0][c][1][field_name]">
<input type="submit" value="OK">
<form>
<pre>
<?php
if (isset($_POST['field']))
print_r($_POST['field']);
?>
</pre>
I got the following response (after entering the word "hello" into the text box and clicking the "OK" button):
Array ( [a] => Array ( [2] => Array ( [b] =>
Array ( [0] => Array ( [c] => Array ( [1] =>
Array ( [field_name] => hello ) ) ) ) ) ) )
Admittedly, it was formatted nicer, but I am posting from my smartphone, so, please, forgive me for not formatting it again manually.
So, to me it is not quite clear why OP needs extra code to solve his/her problem.

Answer 5

Here is your solution:
https://codebrace.com/editor/b06588218
I have used regex match twice to match variable name and arrays
/[(.+?)]/
matches any values in the array where "?" is lazy matching.
while following regex
/^[^[]+/ matches the variable name.
I have used variable variables to create variable from string extracted from above regex
Result:
Array
(
[a] => Array
(
[2] => Array
(
[b] => Array
(
[0] => Array
(
[c] => Array
(
[1] => Array
(
[field_name] => value
)
)
)
)
)
)
)
I hope this helps