處理for-each循環

Question

我有一個for-each循環，內for-each循環

類似於：

foreach ($arr1 as $v1) { 
    foreach ($v1 as $v2) { 
      [ processing goes here ] 
    } 
} 

現在我需要處理僅對第一外環，不是每隔一段時間。

我該怎麼辦？

Answer 1

$clone = $arr1; // clone for future use 
foreach (array_shift($clone) as $v2) { // loop for first element of clone of $arr1, if starting index is known, $arr1[0] can be used instead of array_shift($clone) 
      [ processing goes here ] 
    } 

Answer 2

$firstTime = true; 
foreach ($arr1 as $v1) { 
    if($firstTime) { 
     $firstTime = false; 
     foreach ($v1 as $v2) { 
      [ processing goes here ] 
     } 
    } 
} 

Answer 3

foreach ($arr1 as $v1) { 
    foreach ($v1 as $v2) { 
      [ processing goes here ] 
    } 
break; 
} 

或者你可能會做，簡單地說：

foreach ($arr1[0] as $v2) { 
    [ processing goes here ] 
}