PHP - 自动在中文和英文间插入空格

//将汉字与英文、数字、下划线之间添加一个空格
function insert_spacing($str) {
  $str = preg_replace('/([\x{4e00}-\x{9fa5}]+)([A-Za-z0-9_]+)/u', '${1} ${2}', $str);
  $str = preg_replace('/([A-Za-z0-9_]+)([\x{4e00}-\x{9fa5}]+)/u', '${1} ${2}', $str);
  return $str;
}

参考资料

https://www.hangge.com/blog/cache/detail_1642.html
https://blog.csdn.net/yinlongfei_love/article/details/82219994