php 数组结合

<?php<br />$set = array('a','b','c','d');<br />$len = count($set);<br />$res = array();<br />for($i=0,$k=$len;$i<$len;$i++){<br />  $res[$i] = $set[$i];<br />  for($j=$i+1;$j<$len;$j++){<br />    $res[$k++] = $set[$i].$set[$j];<br />  }<br />}<br />ksort($res);<br />var_dump($res);<br />?>

array (size=10)<br />  0 => string 'a' (length=1)<br />  1 => string 'b' (length=1)<br />  2 => string 'c' (length=1)<br />  3 => string 'd' (length=1)<br />  4 => string 'ab' (length=2)<br />  5 => string 'ac' (length=2)<br />  6 => string 'ad' (length=2)<br />  7 => string 'bc' (length=2)<br />  8 => string 'bd' (length=2)<br />  9 => string 'cd' (length=2)<br />

<br />$set = array('a','b','c','d');<br />$arr=array();<br />for($j=0;$j<sizeof($set);$j++){<br />    $arr[]=$set[$j];<br />}<br />foreach($set as $k=>$v){<br />    for($i=$k;$i<=(3-$v);$i++){<br />        if($v==$set[$i]) continue;<br />        $arr[]=$v.$set[$i];<br />    }<br />}<br />print_r($arr);<br />

<br />Array<br />(<br />    [0] => a<br />    [1] => b<br />    [2] => c<br />    [3] => d<br />    [4] => ab<br />    [5] => ac<br />    [6] => ad<br />    [7] => bc<br />    [8] => bd<br />    [9] => cd<br />)<br /><br />