Equivalent functions in Swift 2 of Java's charAt() and indexOf() ?
Did you read the NSString documentation?
NSString are not identical, but as mentioned by this answer most functions are more or less the same. Anyway, the two exact functions you ask for are right there:
func characterAtIndex(_ index: Int) -> unichar
func rangeOfString(_ searchString: String) -> NSRange
NSRange data type contains just 2 variables:
length that tell you where the substring is in the original string and how long it is. See the documentation.
//Java "abc".indexOf("b") => 1 //Swift "abc".rangeOfString("b").location #=> 1