重复重复字符，重复数量，然后是字符

Question

EX输入：

'ZZYYYYXXXWWVZZ'

指示输出：'3Z4Y3X2W1V2Z'

我尝试过的编码

<?php
$str = "zzzyyyyxxxwwvzz";
$strArray = count_chars($str, 1);

foreach ($strArray as $key => $value)
{
    echo $value.chr($key);
}
?>

输出为：5Z4Y3X2W1V

使用

STR_SPLIT

函数，在阵列中获取给定字符串中的所有字符

Answer 1

现在，使用基本的循环和有条件，并存储以前的字符，您可以确定是否连续，因此可以生成输出字符串。

• 尝试以下（代码注释中的说明）：

  $input = 'zzzyyyyxxxwwvzz';
  
  // Split full string into array of single characters
  $input_chars = str_split($input);
  
  // initialize some temp variables
  $prev_char = '';
  $consecutive_count = 0;
  
  $output = '';
  
  // Loop over the characters
  foreach ($input_chars as $char) {
  
      // first time initialize the previous character
      if ( empty($prev_char) ) {
          $prev_char = $char;
          $consecutive_count++;
      } elseif ($prev_char === $char) { // current character matches previous character
          $consecutive_count++;
      } else { // not consecutive character
          // add to output string
          $output .= ($consecutive_count . $prev_char);
  
          // set current char as new previous_char
          $prev_char = $char;
          $consecutive_count = 1;
      }
  }
  
  // handle remaining characters
  $output .= ($consecutive_count . $prev_char);
  echo $output;

RextesterDemo

preg_replace_callback()

是用于计数连续重复字符并将计数注入就位的直接工具。 demo

$str = "zzzyyyyxxxwwvzz";

echo preg_replace_callback(
         '/(.)\1*/',
         fn($m) => strlen($m[0]) . $m[1],
         $str
    );
// 3z4y3x2w1v2z

Answer 2