Question

Since years I’m wondering why there is no method containsIgnoreCase in the class String. We have equals and equalsIgnoreCase, but there is only contains and no containsIgnoreCase. Is there a reason for that?

Answer 1

It’s really impossible to say what the exact reason was. Perhaps it was felt that equals would be used more frequently than contains and so it would prove most useful to implement an equalsIgnoreCase method, but not all that useful to implement containsIgnoreCase. In any case, it’s hard to be sure. Having said that, you can indeed easily implement your own method in terms of the original contains method, something along these lines could work:

String s1 = "HeLlO WoRlD";
String s2 = "llo worl";
System.out.println(s1.toLowerCase().contains(s2.toLowerCase()));  // true