Question

我正在尝试查找给定字符串的所有可能的2个字母组合。有没有更快的方法，比按位置应用子串位置然后再次调用函数？

以下是我正在尝试的内容：

function permute($str) {
    if (strlen($str) < 2) {
        return array($str);
    }

    $permutations = array();
    $tail = substr($str, 1);

    foreach (permute($tail) as $permutation) {
        $length = strlen($permutation);
        for ($i = 0; $i <= $length; $i++) {
            $permutations[] = substr($permutation, 0, $i) . $str[0] . substr($permutation, $i);
        }
    }
    return $permutations;
}

$str = "tone";

$permutations = array_unique(permute($str));

$str1 = substr_replace($str, "", 1,2);
$permutations = array_unique(permute($str1));

鉴于上面的字符串“音调”，我想得到答案：

to
tn
te
on
oe
ne
ot
nt
et
no
eo
en

Answer 1

如果你想使用substr

function str2array($string) {
    $strArray = [];
    for ($i = 0; $i < strlen($string); $i++) {
        $strArray[] = substr($string, $i, 1);
    }
    return $strArray;
}

但请改用str_split。

$string = 'tone';
$strArray = str_split($string);

foreach ($strArray as $key => $char1) {
    $strArray2 = $strArray;
    unset($strArray2[$key]);
    foreach ($strArray2 as $char2) {
        $permutations[] = $char1 . $char2;
    }
}
//EDIT: adding array_unique in case of dupes
$uniquePermutations=array_unique($permutations);
print_r($uniquePermutations);

阵（ [0] =＆gt;至 [1] =＆gt; TN [2] =＆gt; TE [3] =＆gt; OT [4] =＆gt;上 [5] =＆gt; OE [6] =＆gt; NT [7] =＆gt;没有 [8] =＆gt; NE [9] =＆gt;等 [10] =＆gt; EO [11] =＆gt;恩）

使用PHP查找给定字符串中所有可能的2个字母组合

1 个答案: