php - PHP替换字符串中的随机词

Question

我想替换一个随机单词，其中一个字符串中包含多个单词。

假设字符串是

$str = 'I like blue, blue is my favorite colour because blue is very nice and blue is pretty';

假设我想用红色替换蓝色一词，但在随机位置仅2次。

所以完成一个功能后，输出可能像

I like red, blue is my favorite colour because red is very nice and blue is pretty

另一个可能是

I like blue, red is my favorite colour because blue is very nice and red is pretty

因此，我想多次替换相同的单词，但每次都在不同的位置。

我想到使用preg_match，但是没有选择peing替换的单词的位置也是随机的。

有人知道如何实现这一目标吗？

Answer 1

就像我不愿意在正则表达式上使用正则表达式一样，为了保证正好n个替换，我认为它可以在这里有所帮助，因为它允许轻松使用array_rand()，它确实可以完成您的工作想要-从不确定长度的列表中选择n个随机项目（IMPROVED）。

<?php

    function replace_n_occurences ($str, $search, $replace, $n) {

        // Get all occurences of $search and their offsets within the string
        $count = preg_match_all('/\b'.preg_quote($search, '/').'\b/', $str, $matches, PREG_OFFSET_CAPTURE);

        // Get string length information so we can account for replacement strings that are of a different length to the search string
        $searchLen = strlen($search);
        $diff = strlen($replace) - $searchLen;
        $offset = 0;

        // Loop $n random matches and replace them, if $n < 1 || $n > $count, replace all matches
        $toReplace = ($n < 1 || $n > $count) ? array_keys($matches[0]) : (array) array_rand($matches[0], $n);
        foreach ($toReplace as $match) {
            $str = substr($str, 0, $matches[0][$match][1] + $offset).$replace.substr($str, $matches[0][$match][1] + $searchLen + $offset);
            $offset += $diff;
        }

        return $str;

    }

    $str = 'I like blue, blue is my favorite colour because blue is very nice and blue is pretty';

    $search = 'blue';
    $replace = 'red';
    $replaceCount = 2;

    echo replace_n_occurences($str, $search, $replace, $replaceCount);

See it working