Question

这是我的阵列：

$arr = array("pic0", "pic1", "pic2", "pic3", "pic4");

我如何获得以下字符串：

$str1 = "pic1,pic2,pic3,pic4,pic0";
$str2 = "pic0,pic2,pic3,pic4,pic1";
$str3 = "pic0,pic1,pic3,pic4,pic2";
$str4 = "pic0,pic1,pic2,pic4,pic3";
$str5 = "pic0,pic1,pic2,pic3,pic4";

Answer 1

下面的代码采用数组并在给定索引的情况下对其进行排序。并返回一个逗号分隔的字符串与数组项。例如，此代码将采用第1个元素[0]＆＃34; pic0＆＃34;并把它放在字符串的末尾。

返回一串＆＃34; pic1，pic2，pic3，pic4，pic0＆＃34;

$arr = array("pic0", "pic1", "pic2", "pic3", "pic4");

echo sort_by_index_to_string(0, $arr);

function sort_by_index_to_string($num, $arr)
{
  $v = $arr[$num];
  unset($arr[$num]);
  $arr[$num] = $v;

  return implode(",", $arr);
}

Answer 2

我使用数组，而不是五个字符串：

$arr = array ("pic0", "pic1", "pic2", "pic3", "pic4");
$final = array ();

for($i=1, $c = count($arr); $i <= $c; ++$i) // loop n times
{
    $tmp = $arr; // tmp array
    $x = $arr[$i-1]; // get element to put in the end
    unset($tmp[$i-1]); // unset from the tmp array
    $final[$i] = implode(",", $tmp) . "," . $x; // concatenate the array with $x in the end
}

print_r($final);

/*
Array
(
    [1] => pic1,pic2,pic3,pic4,pic0
    [2] => pic0,pic2,pic3,pic4,pic1
    [3] => pic0,pic1,pic3,pic4,pic2
    [4] => pic0,pic1,pic2,pic4,pic3
    [5] => pic0,pic1,pic2,pic3,pic4
)
*/

如何根据php中的键索引对数组进行排序

2 个答案: