How do I make indexOf not case-sensitive?

Both String#includes() and String#indexOf() are case sensitive. Neither function supports regular expressions. To do case insensitive search, you can use regular expressions and the String#match() function, or you can convert both the string and substring to lower case using the String#toLowerCase() function .

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How do I use ignore case?

You ignore case when you treat the data, not when you retrieve/store it . If you want to store everything in lowercase use String#toLowerCase, in uppercase use String#toUpperCase. Then when you have to actually treat it, you may use out of the bow methods, like String#equalsIgnoreCase(java.

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