php PHP根据相等的值将数组分成组

PHP splitting arrays into groups based on equal values

提问by user2419708

I have an Array containing arrays with 2 values, the first one is the Number of the Author the second is his Affiliation.

我有一个包含具有 2 个值的数组的数组，第一个是作者的编号，第二个是他的隶属关系。

Array ( 
    [0] => Array ( 
            [0] => 2 
            [1] => Department of General Chemistry
        ) 
    [1] => Array ( 
            [0] => 3 
            [1] => Institute of Silicate Materials
        ) 
    [2] => Array ( 
            [0] => 4 
            [1] => Department of General Chemistry
        ) 
    [3] => Array ( 
            [0] => 5 
            [1] => Department of General Chemistry
        ) 
    [4] => Array ( 
            [0] => 6 
            [1] => Institute of Silicate Materials
        ) 
)

How can I group the Authors if the Affiliation is the same? I need the output to be something like:

如果隶属关系相同，我如何将作者分组？我需要输出是这样的：

3,6 Institute of Silicate Materials
2,4,5 Department of General Chemistry

回答by Seth McClaine

foreach ($array as $key => $value) {
 $return[$value[1]][] = $value[0];
}

foreach ($return as $key => $value) {
  echo implode(',', $value)." ".$key;
}

回答by Jonathan Kuhn

<?php
//the array
$data = array(array(2,'Department of General Chemistry'),array(3,'Institute of Silicate Materials'),array(4,'Department of General Chemistry'),array(5,'Department of General Chemistry'),array(6,'Institute of Silicate Materials'));

//a new array to store the data    
$newData = array();

//loop over each value in the data
foreach($data as $d){
    //check if a key exists under the new data for the common value (affiliation)
    if(!isset($newData[$d[1]])){
        //doesn't exist, group under the common value (affiliation)
        $newData[$d[1]] = array(array(),$d[1]);
    }
    //add the author under it's affiliation
    $newData[$d[1]][0][] = $d[0];
}

//get the values from the new data, this resets the keys
$newData = array_values($newData);

//display the data
echo '<pre>'.print_r($newData,1).'</pre>';

example

例子

results in:

结果是：

Array
(
    [0] => Array
        (
            [0] => Array
                (
                    [0] => 2
                    [1] => 4
                    [2] => 5
                )

            [1] => Department of General Chemistry
        )

    [1] => Array
        (
            [0] => Array
                (
                    [0] => 3
                    [1] => 6
                )

            [1] => Institute of Silicate Materials
        )

)

回答by Mehdi Karamosly

Try this code , it should solve your problem:

试试这个代码，它应该可以解决你的问题：

<?php
$element = array ( 
    array ( 
            2 
            ,'Department of General Chemistry'
        ) ,
    array ( 
            3, 
            'Institute of Silicate Materials'
        ), 
    array ( 
            4 
            , 'Department of General Chemistry'
        ) ,
    array ( 
            5 
            , 'Department of General Chemistry'
        ) ,
    array ( 
            6 
            , 'Institute of Silicate Materials'
        ) 
);

$res = array();

for($i=0; $i< count($element); $i++){
    $res[$element[$i][1]][] =  $element[$i][0];
}

echo '<pre>';
    var_dump($res);
echo '</pre>';

foreach ($res as $key => $value){
    echo $key .' : '. implode(',',$value). '<br>';
}
?>

回答by Manoj Yadav

You can do it like this:

你可以这样做：

$ar = array ( 
    array( 
        2,
        'Department of General Chemistry'
    ),
    array( 
        3,
        'Institute of Silicate Materials'
    ),
    array( 
        4,
        'Department of General Chemistry'
    ),
    array( 
        5,
        'Department of General Chemistry'
    ), 
    array( 
        6,
        'Institute of Silicate Materials'
    )
);

$result = array();
foreach ($ar as $key => $value) {
    if (array_key_exists($value[1], $result)) {
        $result[$value[1]] .= ',' . $value[0];
    } else {
        $result[$value[1]] = $value[0];
    }
}

foreach ($result as $key => $value) {
    echo $value . ' ' . $key . '<br>';
}