处理for-each循环

Question

我有一个for-each循环，内for-each循环

类似于：

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

现在我需要处理仅对第一外环，不是每隔一段时间。

我该怎么办？

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; 
} 

或者你可能会做，简单地说：

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