How to select all more duplicate multiple array in php-CodePudding

I'm a very beginner php worker who just got to know Stackoverflow.

My requirement is to select the largest value inside the nested array. Let me explain with an example.

$arr = [
    ["id"=>1],
    ["id"=>2],
    ["id"=>2],
    ["id"=>2],
    ["id"=>3],
    ["id"=>4],
    ["id"=>4],
    ["id"=>4]
];

In this array, we have the number 2 and 4, which are repeated the most.

What functions can I use to do this?

CodePudding user response：

You can do something like this:-

<?php

$arr = [
    ["id"=>1],
    ["id"=>2],
    ["id"=>2],
    ["id"=>2],
    ["id"=>3],
    ["id"=>4],
    ["id"=>4],
    ["id"=>4]
];

$repeatedArr = array();

foreach($arr as $key => $data) {
    foreach($data as $id => $value) {
        if(array_key_exists($value, $repeatedArr)) {
            $repeatedArr[$value]  ;
        } else {
            $repeatedArr[$value] = 1;
        }
    }
}

foreach($repeatedArr as $key => $value) {
    echo $key . " is repeated " . $value . " times\r\n";
}

CodePudding user response：

This would be an approach:

<?php
$data = [
    ["id"=>1],
    ["id"=>2],
    ["id"=>2],
    ["id"=>2],
    ["id"=>3],
    ["id"=>4],
    ["id"=>4],
    ["id"=>4]
];
$counts = [];
array_walk($data, function($entry) use (&$counts) {
    $counts[$entry["id"]]  ;
});
var_dump($counts);

The output obviously is:

Array
(
    [1] => 1
    [2] => 3
    [3] => 1
    [4] => 3
)

CodePudding user response：

You can leverage array_count_values.

<?php

$data = [
    ["id"=>1],
    ["id"=>2],
    ["id"=>2],
    ["id"=>2],
    ["id"=>3],
    ["id"=>4],
    ["id"=>4],
    ["id"=>4]
];

$ids       = array_column($data, 'id', null);
$id_counts = array_count_values($ids);
$max_ids   = array_keys($id_counts, max($id_counts));
var_export($max_ids);

Output:

array (
  0 => 2,
  1 => 4,
)

CodePudding user response：

As you asked to "select the largest value"...

If you want to return the array holding the largest value...

max($arr)

will return ["id"=>4]

If you want only the value returned...

array_values(max($arr))[0]

will return (int)4