Convert associative multidimensional array into single-dimensional array with treepath keys [duplicate] - php

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Closed 10 years ago.
Possible Duplicate:
PHP convert nested array to single array while concatenating keys?
Get array's key recursively and create underscore seperated string
Please, read the whole question before answering.
I have this multidimensional array:
$data = array(
'user' => array(
'email' => 'user#example.com',
'name' => 'Super User',
'address' => array(
'billing' => 'Street 1',
'delivery' => 'Street 2'
)
),
'post' => 'Hello, World!'
);
I want it flatten, transformed into:
$data = array(
'user.email' => 'user#example.com',
'user.name' => 'Super User',
'user.address.billing' => 'Street 1',
'user.address.delivery' => 'Street 2',
'post' => 'Hello, World!'
);
Important:
The keys are very important to me. I want them concatenated, separated by periods.
It should work with any level of nesting.
Thank you!

Answer 1

Something like this should work:
function flatten($array, $prefix = '') {
$result = array();
foreach($array as $key=>$value) {
if(is_array($value)) {
$result = $result + flatten($value, $prefix . $key . '.');
}
else {
$result[$prefix . $key] = $value;
}
}
return $result;
}
DEMO

Answer 2

Thanks for all the given answers.
I have transformed it in the following, which is an improved version. It eliminates the need of a root prefix, does not need to use references, it is cleaner to read, and it has a better name:
function array_flat($array, $prefix = '')
{
$result = array();
foreach ($array as $key => $value)
{
$new_key = $prefix . (empty($prefix) ? '' : '.') . $key;
if (is_array($value))
{
$result = array_merge($result, array_flat($value, $new_key));
}
else
{
$result[$new_key] = $value;
}
}
return $result;
}

Answer 3

Try this
<?php
$data = array(
'user' => array(
'email' => 'user#example.com',
'name' => 'Super User',
'address' => array(
'billing' => 'Street 1',
'delivery' => 'Street 2'
)
),
'post' => 'Hello, World!'
);
function prefixKey($prefix, $array)
{
$result = array();
foreach ($array as $key => $value)
{
if (is_array($value))
$result = array_merge($result, prefixKey($prefix . $key . '.', $value));
else
$result[$prefix . $key] = $value;
}
return $result;
}
var_dump(prefixKey('', $data));
?>
Outputs
array
'user.email' => string 'user#example.com' (length=16)
'user.name' => string 'Super User' (length=10)
'user.address.billing' => string 'Street 1' (length=8)
'user.address.delivery' => string 'Street 2' (length=8)
'post' => string 'Hello, World!' (length=13)

Answer 4

test this out here
i passed by reference so no need for returns. just hand over the array storage.
$store = array();
function flatten($array,&$storage,$parentKey = ''){
foreach($array as $key => $value){
$itemKey = (($parentKey)? $parentKey.'.':'').$key;
if(is_array($value)){
flatten($value,$storage,$itemKey);
} else {
$storage[$itemKey] = $value;
}
}
}
flatten($data,$store);
var_dump($store);

Answer 5

Use recursion such as this:
function process_data( $data, $parent_key ){
if ( ! is_array( $data ) ){
return $data;
}
$flattened_array = array();
foreach( $data as $key => $item ){
$flattened_key = $parent_key . '.' . $key;
$flattened_array[ $flattened_key ] = process_data( $item, $flattened_key );
}
return $flattened_array;
}