在字符串中搜索子字符串

   //在字符串中搜索子字符串

        NSRange aRange;

        NSString *big = @"abbakachakazazzz";

        NSString *small = @"KA";

        

//        NSCaseInsensitiveSearch = 1,

//        NSLiteralSearch = 2,        /* Exact character-by-character equivalence */

//        NSBackwardsSearch = 4,        /* Search from end of source string */

//        NSAnchoredSearch = 8,        /* Search is limited to start (or end, if NSBackwardsSearch) of source string */

//        NSNumericSearch = 64,

        aRange = [big rangeOfString:small options:NSCaseInsensitiveSearch|NSBackwardsSearch];