为此 str_replace 。如果对前两个参数使用数组，则可以定义一组单词和替换：

You can use str_replace for this. If you use arrays for the first two arguments, you can define a set of words and replacements:

echo str_replace(['Ipad', 'Iphone'], ['iPad', 'iPhone'], ucwords(strtolower($string)));

来自文档：

如果搜索和替换是数组，则str_replace（）从每个数组中获取一个值，并使用它们对主题进行搜索和替换。

If search and replace are arrays, then str_replace() takes a value from each array and uses them to search and replace on subject.