計數等於數組的相鄰值

Question

我正在尋找一個函數來計算數組的相鄰元素。 這裏一個例子：

Array(A,A,A,B,B,C,A,A,A,C,C…) 

函數返回：

3*A, 2*B, 1*C, 3*A, 2*C,... 

你知道任何這樣的功能呢？

Answer 1

這應該可以做到。如果沒有警告，

<? 

function arrayCountAdjacent($array) { 
    $adjacentArray = array(); 
    $lastValue = null; 
    $i = 0; 
    foreach ($array as $key => $value) { 
     if ($lastValue === null || $lastValue != $value) { 
      $i++; 
      $adjacentArray[$i] = array("value" => $value, "count" => 1); 

      $lastValue = $value; 
     } 
     else { 
      $adjacentArray[$i]["count"]++; 
     } 
    } 

    return $adjacentArray; 
} 

$array = array("A", "A", "A", "B", "B", "C", "A", "A", "A", "C"); 
var_dump(arrayCountAdjacent($array)); 

foreach(arrayCountAdjacent($array) as $result) 
{ 
    echo $result['count'] ."*". $result['value']."\n"; 
} 

Answer 2

這應該這樣做，沒有通知/警告。

$data = array("A","A","A","B","B","C","A","A","A","C"); 
foreach($data as $val){ 
    if(!isset($newarray[$val])){$newarray[$val]=0;} 
    $newarray[$val]++; 
} 
print_r($newarray); 

輸出

Array ([A] => 6 [B] => 2 [C] => 2) 

或者

$data = array("A","A","A","B","B","C","A","A","A","C"); 
foreach($data as $val){ 
    if(!isset($newarray[$val])){$newarray[$val]=0;} 
    $newarray[$val]++; 
} 

foreach($newarray as $key=>$val){ 
    echo $val.'*'.$key.', '; 
} 

輸出

6*A, 2*B, 2*C, 

這應該做工精細;）

Dom

Answer 3

$myArray = array('A','A','A','B','B','C','A','A','A','C','C'); 

$counts = array_reduce(
    array_keys($myArray), 
    function (&$counter, $key) use ($myArray) { 
     static $last = -1; 

     if (($key > 0) && ($myArray[$key] == $myArray[$key-1])) { 
      list($char, $count) = explode('*',$counter[$last]); 
      $counter[$last] = $char . '*' . ++$count; 
     } else { 
      $counter[++$last] = $myArray[$key] . '*1'; 
     } 
     return $counter; 
    }, 
    array() 
); 

var_dump($counts);