PHP: remove element from multidimensional array (by key) using foreach - php

Question

I got multidimensional array. From each subarray, I would like to remove / unset values with index 1. My array $data.
Array
(
[3463] => Array
(
[0] => 1
[1] => 2014
[context] => 'aaa'
)
[3563] => Array
(
[0] => 12
[1] => 2014
[context] => 'aaa'
)
[2421] => Array
(
[0] => 5
[1] => 2014
[context] => 'zzz'
)
)
I would like to remove every element with index '1' from subarrays. Desired output is:
Array
(
[3463] => Array
(
[0] => 1
[context] => 'aaa'
)
[3563] => Array
(
[0] => 12
[context] => 'aaa'
)
[2421] => Array
(
[0] => 5
[context] => 'zzz'
)
)
Why this does not work?
foreach ($data as $subArr) {
foreach ($subArr as $key => $value) {
if ($key == '1') {
unset($subArr[$key]);
}
}
}
I'm sorry if this problem is trivial for you guys.

Answer 1

easy way!?
you can do this just with one foreach!
foreach ($data as $key => $subArr) {
unset($subArr['1']);
$data[$key] = $subArr;
}

Answer 2

you are making changes in subarray instead of main one try this may help
foreach ($data as $key => $subArr) {
unset($data[$key][1]);
}

Answer 3

It does not work because $subArr from the outer foreach contains copies of the values of $data and the inner foreach modifies these copies, leaving $data not touched.
You can fix that by telling PHP to make $subArr references to the original values stored in $data:
foreach ($data as &$subArr) {
foreach ($subArr as $key => $value) {
if ($key == '1') {
unset($subArr[$key]);
}
}
}
Another option is to use function array_map(). It uses a callback function that can inspect (and modify) each value of $data and it returns a new array.
$clean = array_map(
function (array $elem) {
unset($elem['1']); // modify $elem
return $elem; // and return it to be put into the result
},
$data
);
print_r($clean);

Answer 4

try this:
<?php
$data = Array
(
'3463' => Array
(
'0' => 1,
'1' => 2014,
'context' => 'aaa'
),
'3563' => Array
(
'0' => 12,
'1' => 2014,
'context' => 'aaa'
),
'2421' => Array
(
'0' => 5,
'1' => 2014,
'context' => 'zzz'
)
);
foreach ($data as $k=>$subArr) {
foreach ($subArr as $key => $value) {
if ($key == '1') {
unset($data[$k][$key]);
}
}
}
print_r($data);// display the output