检查，如果当前元素为最后一个元素

Question

请帮我翻译这个伪代码，以真正的PHP代码：

foreach ($arr as $k => $v) 
    if (THIS IS NOT THE LAST ELEMENT IN THE ARRAY) 
     doSomething(); 

编辑：数组可以具有数字或字符串键

Answer 1

您可以使用PHP的end()

$array = array('a' => 1,'b' => 2,'c' => 3); 
$lastElement = end($array); 
foreach($array as $k => $v) { 
    echo $v . '<br/>'; 
    if($v == $lastElement) { 
     // 'you can do something here as this condition states it just entered last element of an array'; 
    } 
} 

UPDATE1

正如@Mijoja指出的那样，如果在数组中有多次相同的值，那么上面的代码可能会有问题。下面是它的修复。

$array = array('a' => 1, 'b' => 2, 'c' => 3, 'd' => 2); 
//point to end of the array 
end($array); 
//fetch key of the last element of the array. 
$lastElementKey = key($array); 
//iterate the array 
foreach($array as $k => $v) { 
    if($k == $lastElementKey) { 
     //during array iteration this condition states the last element. 
    } 
} 

UPDATE2

我找到解决方案通过@onteria_会更好然后什么我已经回答了，因为它不修改数组内部指针，我更新的答案，以配合他的回答。

$array = array('a' => 1, 'b' => 2, 'c' => 3, 'd' => 2); 
// Get array keys 
$arrayKeys = array_keys($array); 
// Fetch last array key 
$lastArrayKey = array_pop($arrayKeys); 
//iterate array 
foreach($array as $k => $v) { 
    if($k == $lastArrayKey) { 
     //during array iteration this condition states the last element. 
    } 
} 

谢谢@onteria_

Answer 2

$myarray = array(
    'test1' => 'foo', 
    'test2' => 'bar', 
    'test3' => 'baz', 
    'test4' => 'waldo' 
); 

$myarray2 = array(
'foo', 
'bar', 
'baz', 
'waldo' 
); 

// Get the last array_key 
$last = array_pop(array_keys($myarray)); 
foreach($myarray as $key => $value) { 
    if($key != $last) { 
    echo "$key -> $value\n"; 
    } 
} 

// Get the last array_key 
$last = array_pop(array_keys($myarray2)); 
foreach($myarray2 as $key => $value) { 
    if($key != $last) { 
    echo "$key -> $value\n"; 
    } 
} 

由于array_pop由array_keys创建的临时阵列上的作品不修改原始数组的。

$ php test.php 
test1 -> foo 
test2 -> bar 
test3 -> baz 
0 -> foo 
1 -> bar 
2 -> baz 

Answer 3

如果项目按数字排序，则使用key（）函数确定当前项目的索引并将其与长度进行比较。你必须通过的项目在一个while循环使用的next（）或prev（）循环，而不是一个for循环：

$length = sizeOf($arr); 
while (key(current($arr)) != $length-1) { 
    $v = current($arr); doSomething($v); //do something if not the last item 
    next($myArray); //set pointer to next item 
} 

Answer 4

$arr = array(1, 'a', 3, 4 => 1, 'b' => 1); 
foreach ($arr as $key => $val) { 
    echo "{$key} = {$val}" . (end(array_keys($arr))===$key ? '' : ', '); 
} 
// output: 0 = 1, 1 = a, 2 = 3, 4 = 1, b = 1 

Answer 5

这永远不会把戏对我来说

foreach($array as $key => $value) { 
    if (end(array_keys($array)) == $key) 
     // Last key reached 
} 

编辑30/04/15

$last_key = end(array_keys($array)); 
reset($array); 

foreach($array as $key => $value) { 
    if ($key == $last_key) 
     // Last key reached 
} 

为了避免@Warren塞尔让

提到E_STRICT警告0

$array_keys = array_keys($array); 
$last_key = end($array_keys); 

Answer 6

我的解决办法，也很简单..

$array = [...]; 
$last = count($array) - 1; 

foreach($array as $index => $value) 
{ 
    if($index == $last) 
     // this is last array 
    else 
     // this is not last array 
} 

Answer 7

我这里知道这是旧的，并且使用SPL迭代器也许只是一个矫枉过正，但无论如何，另一种解决方案：

$ary = array(1, 2, 3, 4, 'last'); 
$ary = new ArrayIterator($ary); 
$ary = new CachingIterator($ary); 
foreach ($ary as $each) { 
    if (!$ary->hasNext()) { // we chain ArrayIterator and CachingIterator 
          // just to use this `hasNext()` method to see 
          // if this is the last element 
     echo $each; 
    } 
} 

Answer 8

为什么不用这个非常简单的方法：

$i = 0; //a counter to track which element we are at 
foreach($array as $index => $value) { 
    $i++; 
    if($i == sizeof($array)){ 
     //we are at the last element of the array 
    } 
}