explode()在空格上，然后使用[]表示法以数组形式访问结果字符串：

$words = explode(" ", "Community College District");
$acronym = "";

foreach ($words as $w) {
  $acronym .= $w[0];
}

如果您期望多个空格可以分隔单词，请改用 preg_split()

$words = preg_split("/\s+/", "Community College District");

或者-,_，例如，如果非空格字符分隔单词（），请同时使用preg_split()：

// Delimit by multiple spaces, hyphen, underscore, comma
$words = preg_split("/[\s,_-]+/", "Community College District");