php multidimensional array to single dimensional array [duplicate] - php

Question

This question already has answers here:
Is there a function to extract a 'column' from an array in PHP?
(15 answers)
Closed 6 months ago.
I have an array
array(5) {
[0]=>
array(1) {
["id"]=>
string(1) "5"
}
[1]=>
array(1) {
["id"]=>
string(1) "6"
}
[2]=>
array(1) {
["id"]=>
string(1) "7"
}
[3]=>
array(1) {
["id"]=>
string(1) "8"
}
[4]=>
array(1) {
["id"]=>
string(1) "9"
}
}
I wan to make my array like:
$registrationIDs = array( "5","6","7","8","9");
I am trying this code but not working
$results = array();
foreach($result as $inner) {
$results[key($inner)] = current($inner);
}
How do I effeciently transform arrays like this

Answer 1

Try with array_map.
$results = array_map (function ($e) { return $e['id']; }, $inner);
http://php.net/manual/en/function.array-map.php
By the way, if you still want to do it your way, try this form of foreach :
$results = array ();
foreach ($inner as $key => $value)
$results[$key] = $value['id'];

Answer 2

$array = [['id'=>1],['id'=>2],['id'=>3],['id'=>4],['id'=>5],];
$result = call_user_func_array('array_merge_recursive', $array);
var_dump($result['id']);
//array(5) {
// [0] =>
// int(1)
// [1] =>
// int(2)
// [2] =>
// int(3)
// [3] =>
// int(4)
// [4] =>
// int(5)
//}

Answer 3

Ok, I saw a lot of answers, so I wondered what to better answer was.
<?php
$data = array ();
for ($i = 0; $i < 1000000; $i++)
$data[$i] = array ('id' => rand ());
$time0 = microtime (true);
// Niols (1)
$results = array_map (function ($e) { return $e['id']; }, $data);
$time1 = microtime (true);
// Niols (2)
$results = array ();
foreach ($data as $key => $value)
$results[$key] = $value['id'];
$time2 = microtime (true);
// User (1)
$it = new RecursiveIteratorIterator(new RecursiveArrayIterator($data));
$results = iterator_to_array($it, false);
$time3 = microtime (true);
// User (2)
$results = array();
foreach ($data as $datum)
$results = array_merge($results, $datum);
$time4 = microtime (true);
// sectus
$results = call_user_func_array('array_merge_recursive', $data);
$time5 = microtime (true);
// Pankaj katiyar and Ghost
$results = array_column($data, 'id');
$time6 = microtime (true);
var_dump ($time1-$time0);
var_dump ($time2-$time1);
var_dump ($time3-$time2);
var_dump ($time4-$time3);
var_dump ($time5-$time4);
var_dump ($time6-$time5);
On my computer, this outputs :
float(0.62708687782288)
float(0.35285401344299)
float(1.5429890155792)
float(0.7408618927002)
float(0.70525908470154)
float(0.15015292167664)
Conclusion :
array_column is ultra-efficient (but PHP 5.5+). Writing a simple foreach seems quite efficient too.

Answer 4

You can try with below code.
I think this is working fine.
Process 1:-
$it = new RecursiveIteratorIterator(new RecursiveArrayIterator($data));
$l = iterator_to_array($it, false);
var_dump($l); // one Dimensional
Process 2:-
Try with:
$input = array(/* your array*/);
$output = array();
foreach ( $input as $data ) {
$output = array_merge($output, $data);
}

Answer 5

Try this:
$array = array(/*your array*/);
$results = array();
foreach ($array as $value)
{
foreach($value as $innerValue)
{
$results[] = $innervalue;
}
}