fun lastIndexOf(string: String): Int

Returns the index within this string builder of the last occurrence of the specified string. The last occurrence of empty string "" is considered to be at the index equal to this.length.

Returns -1 if the specified string does not occur in this string builder.

fun lastIndexOf(string: String, startIndex: Int): Int

Returns the index within this string builder of the last occurrence of the specified string, starting from the specified startIndex toward the beginning.

Returns -1 if the specified string does not occur in this string builder starting at the specified startIndex.