PHP SPLIT array based on key range - php

Question

I've an array.
Array
(
[initial] => MSS
[hour] => 5.2
[row_checker_1] => 1
[project_name_1] => KGD001
[project_shortcode_1] => KGD001
[5_1] => 23
[6_1] => 3.3
[4_1] => 23.2
[remarks_1] => on going
[task_id] => 76
[row_checker_2] => 2
[project_name_2] => DG001
[project_shortcode_2] => DG001
[5_2] => 1.1
[6_2] => 2.2
[4_2] => 3.1
[remarks_2] => on going
)
Now I want to split all element upper range key is "project_shortcode_1" and lower range key is remarks_1.
So, new array should look like:
array
(
[5_1] => 23
[6_1] => 3.3
[4_1] => 23.2
)

Answer 1

Use array_filter with flag ARRAY_FILTER_USE_KEY for using the array keys, and do the comparison with the logic needed to get the desired keys. It works from PHP 5.6.
$arr = array ( "initial" => "MSS",
"hour" => 5.2,
"row_checker_1" => 1,
"project_name_1" => "KGD001",
"project_shortcode_1" => "KGD001",
"5_1" => 23,
"6_1" => 3.3,
"4_1" => 23.2,
"remarks_1" => "on going",
"task_id" => 76,
"row_checker_2" => 2,
"project_name_2" => "DG001",
"project_shortcode_2" => "DG001",
"5_2" => 1.1,
"6_2" => 2.2,
"4_2" => 3.1,
"remarks_2" => "on going",
);
// PHP > 5.6
$result = array_filter($arr, function($k){
$var = explode('_', $k);
return is_numeric($var[0]) && $var[1]==1;
}, ARRAY_FILTER_USE_KEY);

Answer 2

If what you need is a multidimensional array with all the ranges NUMBER_N, then use something like this (extended from Dmitriy Demir answer):
$myArray = array(
'initial' => 'MSS',
'hour' => '5.2',
'row_checker_1' => '1',
'project_name_1' => 'KGD001',
'project_shortcode_1' => 'KGD001',
'5_1' => '23',
'6_1' => '3.3',
'4_1' => '23.2',
'remarks_1' => 'on going',
'task_id' => '76',
'row_checker_2' => '2',
'project_name_2' => 'DG001',
'project_shortcode_2' => 'DG001',
'5_2' => '1.1',
'6_2' => '2.2',
'4_2' => '3.1',
'remarks_2' => 'on going'
);
function splitRange($a){
$newArray = array();
foreach ($a as $k => $v) {
$rightFormat = preg_match('/^\d+_(\d+)$/', $k, $index);
if ($rightFormat)
$newArray[$index[1]][$k] = $v;
}
return $newArray;
}
print_r(splitRange($myArray));
The result will be something like:
Array
(
[1] => Array
(
[5_1] => 23
[6_1] => 3.3
[4_1] => 23.2
)
[2] => Array
(
[5_2] => 1.1
[6_2] => 2.2
[4_2] => 3.1
)
)
being N from NUMBER_N the index of the array.

Answer 3

Since you mentioned in the comments that you'd prefer to get all values that are in format NUMBER_1 I think you'd need to loop through your array and check the value names with regex, then add the values to a new array if they meet the criteria. Here's how I would do this:
$myArray = array(
'initial' => 'MSS',
'hour' => '5.2',
'row_checker_1' => '1',
'project_name_1' => 'KGD001',
'project_shortcode_1' => 'KGD001',
'5_1' => '23',
'6_1' => '3.3',
'4_1' => '23.2',
'remarks_1' => 'on going',
'task_id' => '76',
'row_checker_2' => '2',
'project_name_2' => 'DG001',
'project_shortcode_2' => 'DG001',
'5_2' => '1.1',
'6_2a' => '2.2',
'4_2' => '3.1',
'remarks_2' => 'on going'
);
$newArray = array();
foreach ($myArray as $k => $v) {
$rightFormat = preg_match('/^\d+_\d+$/', $k);
if ($rightFormat)
$newArray[$k] = $v;
}
print_r($newArray);
The result of print_r in that case would be:
Array ( [5_1] => 23 [6_1] => 3.3 [4_1] => 23.2 [5_2] => 1.1 [6_2] =>
2.2 [4_2] => 3.1 )
If the number after the underscore should always be 1 then change the regex from /^\d+_\d+$/ to /^\d+_1$/.
You can play around and see how regex works here.
PS: I've set all values to strings out of convenience. Feel free to modify that.

Answer 4

A regex-based solution seems fitting for this question.
preg_grep() is a function designed to apply a regex filter upon each value in an array. I little more tweaking is necessary for this case because the keys must be filtered instead.
The One-liner:
$output=array_intersect_key($input,array_flip(preg_grep("/^\d+_1$/",array_keys($input)))));
/* array (
'5_1' => 23,
'6_1' => 3.3,
'4_1' => 23.2,
)*/
Here is the step-by-step array manipulation...
array_keys($input); // create array with input keys as values
/* array (
0 => 'initial',
1 => 'hour',
2 => 'row_checker_1',
3 => 'project_name_1',
4 => 'project_shortcode_1',
5 => '5_1',
6 => '6_1',
7 => '4_1',
8 => 'remarks_1',
9 => 'task_id',
10 => 'row_checker_2',
11 => 'project_name_2',
12 => 'project_shortcode_2',
13 => '5_2',
14 => '6_2',
15 => '4_2',
16 => 'remarks_2',
) */
preg_grep("/^\d+_1$/",array_keys($input)); // filter the input array using regex pattern
/* array (
5 => '5_1',
6 => '6_1',
7 => '4_1',
) */
array_flip(preg_grep("/^\d+_1$/",array_keys($input))); // flip the filtered array
/* array (
'5_1' => 5,
'6_1' => 6,
'4_1' => 7,
)*/
array_intersect_key($input,array_flip(preg_grep("/^\d+_1$/",array_keys($input)))); // filter input by comparing keys against filtered array
/* array (
'5_1' => 23,
'6_1' => 3.3,
'4_1' => 23.2,
)*/