我在Stackoverflow上阅读了与此主题相关的大约15个其他资源和答案，并且只找到了一个与我想要的相近的代码，但我不知道如何进一步完善它的生成。
这是我到目前为止所做的：
$combos = array_unique($letters);
$lastres = $letters;
for ($i = 1; $i < count($letters); $i++) {
$newres = array();
foreach ($lastres as $r) {
foreach ($letters as $let) {
$new = $r . $let;
if (!in_array($new, $newres)) {
$newres[] = $new;
// Action
$combos[] = $new;
}
}
}
$lastres = $newres;
}
print_r($combos);
?>
以上代码从输入＆＃34; apple＆＃34;生成1365个结果，但它包含不需要的结果。
我将在此处粘贴前86个结果：
[0] =＆gt; a [1] =＆gt; p [3] =＆gt; l [4] =＆gt; e [5] =＆gt; aa [6] =＆gt; ap [7] =＆gt; al [8] =＆gt; ae [9] =＆gt; pa [10] =＆gt; pp [11] =＆gt; pl [12] =＆gt; pe [13] =＆gt; la [14] =＆gt; lp [15] =＆gt; ll [16] =＆gt; le [17] =＆gt; ea [18] =＆gt; ep [19] =＆gt; el [20] =＆gt; ee [21] =＆gt; aaa [22] =＆gt; aap [23] =＆gt; aal [24] =＆gt; aae [25] =＆gt; apa [26] =＆gt; app [27] =＆gt; apl [28] =＆gt;猿[29] =＆gt; ala [30] =＆gt; alp [31] =＆gt;全部[32] =＆gt; ale [33] =＆gt; aea [34] =＆gt; aep [35] =＆gt; ael [36] =＆gt; aee [37] =＆gt; paa [38] =＆gt; pap [39] =＆gt; pal [40] =＆gt; pae [41] =＆gt; ppa [42] =＆gt; ppp [43] =＆gt; ppl [44] =＆gt; ppe [45] =＆gt; pla [46] =＆gt; plp [47] =＆gt; pll [48] =＆gt; ple [49] =＆gt;豌豆[50] =＆gt; pep [51] =＆gt; pel [52] =＆gt;小便[53] =＆gt; laa [54] =＆gt; lap [55] =＆gt; lal [56] =＆gt; lae [57] =＆gt; lpa [58] =＆gt; lpp [59] =＆gt; lpl [60] =＆gt; lpe [61] =＆gt; lla [62] =＆gt; llp [63] =＆gt; lll [64] =＆gt; lle [65] =＆gt; lea [66] =＆gt; lep [67] =＆gt; lel [68] =＆gt; lee [69] =＆gt; eaa [70] =＆gt; eap [71] =＆gt; eal [72] =＆gt; eae [73] =＆gt; epa [74] =＆gt; epp [75] =＆gt; epl [76] =＆gt; epe [77] =＆gt; ela [78] =＆gt; elp [79] =＆gt; ell [80] =＆gt; ele [81] =＆gt; eea [82] =＆gt; eep [83] =＆gt;鳗鱼[84] =＆gt; eee [85]
世界苹果包含1 A，1 L和1 E，但它包含的结果如＆＃34; aa＆＃34;，＆＃34; ll＆＃34;，＆＃34; ee＆＃34;，＆ ＃34; aaa＆＃34;，＆＃34; lll＆＃34;，＆＃34; eee＆＃34;。我不希望这些包括在我的结果中。
我遇到的另一个问题是我只需要一个特定大小的字母组合的实例（不论顺序如何）。例如：当它生成3个字母组合时，我只需要＆＃34; ple＆＃34;而不是＆＃34; pel＆＃34;，＆＃34; lpe＆＃34;，＆＃34; lep＆＃34;，＆＃34; epl＆＃34;或＆＃34; elp＆＃34;，4个字母，5等相同
我不确定我是否正确接近这个或者我是否正在解释我的意思。
非常感谢任何帮助。
答案 0 :(得分：2)
您正在寻找的东西IMO是一个强大的功能集：
$ cat a.php
<?php
$result = array_values(array_unique(str_split('apples')));
function getPowerSet($str_array) {
$set_size = count($str_array);
$pow_set_size = pow(2, $set_size);
$return = array();
for($counter = 0; $counter < $pow_set_size; $counter++) {
$tmp_str = "";
for($j = 0; $j < $set_size; $j++) {
if($counter & (1 << $j)) {
$tmp_str .= "$str_array[$j]";
}
}
$return[] = $tmp_str;
}
return $return;
}
print_r(getPowerSet($result));
?>
$ php a.php
Array
(
[0] =>
[1] => a
[2] => p
[3] => ap
[4] => l
[5] => al
[6] => pl
[7] => apl
[8] => e
[9] => ae
[10] => pe
[11] => ape
[12] => le
[13] => ale
[14] => ple
[15] => aple
[16] => s
[17] => as
[18] => ps
[19] => aps
[20] => ls
[21] => als
[22] => pls
[23] => apls
[24] => es
[25] => aes
[26] => pes
[27] => apes
[28] => les
[29] => ales
[30] => ples
[31] => aples
)
如果你想要重复字母，例如苹果中的2'p，那么做一个小改动：
$result = str_split('apples');
然后结果将是：
$ php index.php
Array
(
[0] =>
[1] => a
[2] => p
[3] => ap
[4] => p
[5] => ap
[6] => pp
[7] => app
[8] => l
[9] => al
[10] => pl
[11] => apl
[12] => pl
[13] => apl
[14] => ppl
[15] => appl
[16] => e
[17] => ae
[18] => pe
[19] => ape
[20] => pe
[21] => ape
[22] => ppe
[23] => appe
[24] => le
[25] => ale
[26] => ple
[27] => aple
[28] => ple
[29] => aple
[30] => pple
[31] => apple
[32] => s
[33] => as
[34] => ps
[35] => aps
[36] => ps
[37] => aps
[38] => pps
[39] => apps
[40] => ls
[41] => als
[42] => pls
[43] => apls
[44] => pls
[45] => apls
[46] => ppls
[47] => appls
[48] => es
[49] => aes
[50] => pes
[51] => apes
[52] => pes
[53] => apes
[54] => ppes
[55] => appes
[56] => les
[57] => ales
[58] => ples
[59] => aples
[60] => ples
[61] => aples
[62] => pples
[63] => apples
)
在此处详细了解该算法：http://www.geeksforgeeks.org/power-set/