参见 常见问题.

我不相信 ucfirst() 满足 OP 的问题，即在不拆分字符串并稍后加入的情况下将字符串中每个单词的第一个字母大写.

I don't believe ucfirst() satisfies the OP's question to capitalize the first letter of each word in a string without splitting the string and joining it later.