條件基於迭代的位置

Question

一些僞代碼，我想如果可能的話要做到這一點用foreach

我不知道是否可以從陣列獲取的位置

$num = array (1 => 7, 
       2 => 9, 
       3 => 10, 
       4 => 11,); 

foreach ($num as $value) { 

if (first position) { echo $value . '<br> first <br>';} 

elseif (middle position) { echo $value . '<br> middle <br>';} 

elseif (last position) { echo $value . '<br> last';} 


} 

預期結果

7 
first 
9 
middle 
10 
middle 
11 
last 

Answer 1

$num = array (1 => 7, 
       2 => 9, 
       3 => 10, 
       4 => 11); 
$i = 1; 
foreach ($num as $value) { 
    if($i == 1){// if first 
     echo $value.'<br> first<br>'; 
    }else if(count($num) == $i){// if last 
     echo $value.'<br> last'; 
    }else{// if between first and last 
     echo $value.'<br> middle<br>'; 
    } 
    $i++; 
} 

//---output 
/* 
7 
first 
9 
middle 
10 
middle 
11 
last 
*/ 

Answer 2

解決我自己，比ks @ chris85

$num = array (1 => 7, 
      2 => 9, 
      3 => 10, 
      4 => 11,); 

$arrlen = count($num); 

foreach ($num as $key=>$value) { 

if ($key == 1) { echo $value . '<br> first <br>';} 

elseif ($key != $arrlen) { echo $value . '<br> middle <br>';} 

else { echo $value . '<br> last';} 


}