//////////字符串屬性//////////
    NSString *str1 = @"string";
    
    NSLog(@"長度:                   %ld", str1.length);
    NSLog(@"描述:                   %@", str1.description);
    NSLog(@"哈希地址:                %lu", (unsigned long)str1.hash);
    NSLog(@"字符串對應下標字符:        %c", [str1 characterAtIndex:2]);
    //輸出:   長度:                   6
    //輸出:   描述:                   string
    //輸出:   哈希地址:                10152471993823965
    //輸出:   字符串對應下標字符:        r

//截取指定位置之後的字符串
- (NSString *)substringFromIndex:(NSUInteger)from;
//從0下標開始截取到指定位置的字符串
- (NSString *)substringToIndex:(NSUInteger)to;
//截取指定範圍的字符串
- (NSString *)substringWithRange:(NSRange)range;
//截取字符串指定範圍的字符
- (void)getCharacters:(unichar *)buffer range:(NSRange)range;

   //////////字符串比較//////////
//1.比較
- (NSComparisonResult)compare:(NSString *)string;
//2.比較(指定字符串,條件)
- (NSComparisonResult)compare:(NSString *)string options:(NSStringCompareOptions)mask;
//3.比較(指定字符串,條件,範圍)
- (NSComparisonResult)compare:(NSString *)string options:(NSStringCompareOptions)mask range:(NSRange)compareRange;
//4.比較(指定字符串,條件,範圍,本地化)
- (NSComparisonResult)compare:(NSString *)string options:(NSStringCompareOptions)mask range:(NSRange)compareRange locale:(nullable id)locale;
//5.比較(不區分大小寫)
- (NSComparisonResult)caseInsensitiveCompare:(NSString *)string;

//6.本地化比較
- (NSComparisonResult)localizedCompare:(NSString *)string;
//7.本地化比較(不區分大小寫)
- (NSComparisonResult)localizedCaseInsensitiveCompare:(NSString *)string;
//8.本地化比較(標準)
- (NSComparisonResult)localizedStandardCompare:(NSString *)string;

//9.判斷兩個字符串是否內容一致
- (BOOL)isEqualToString:(NSString *)aString;

   //////////字符串拼接//////////
    NSString *string = @"1";
    NSString *appStr = @"2";
    NSString *resultStr1 = [string stringByAppendingString:appStr];
    NSString *resultStr2 = [string stringByAppendingFormat:@" + %@", appStr];
    
    NSLog(@"普通拼接:     %@", resultStr1);
    NSLog(@"格式化拼接:   %@", resultStr2);
    //輸出:   普通拼接:     12
    //輸出:   格式化拼接:   1 + 2

   //////////字符串基本類型轉換//////////
    NSString *numStr = @"87234.2345";

    NSLog(@"double型:        %f", numStr.doubleValue);
    NSLog(@"float型:         %f", numStr.floatValue);
    NSLog(@"int型:           %d", numStr.intValue);
    NSLog(@"NSInteger型:     %ld", numStr.integerValue);
    NSLog(@"long long型:     %lld", numStr.longLongValue);
    NSLog(@"BOOL型:          %d", numStr.boolValue);
    //輸出:   double型:        87234.234500
    //輸出:   float型:         87234.234375
    //輸出:   int型:           87234
    //輸出:   NSInteger型:     87234
    //輸出:   long long型:     87234
    //輸出:   BOOL型:          1

    //////////字符串大小寫轉換//////////
    NSString *string = @"string";

    NSLog(@"大寫:         %@", string.uppercaseString);
    NSLog(@"小寫:         %@", string.lowercaseString);
    NSLog(@"首字母大寫:    %@", string.capitalizedString);
    //輸出:   大寫:         STRING
    //輸出:   小寫:         string
    //輸出:   首字母大寫:    String

//本地化(大寫)
- (NSString *)uppercaseStringWithLocale:(nullable NSLocale *)locale; 
//本地化(小寫)
- (NSString *)lowercaseStringWithLocale:(nullable NSLocale *)locale;
//本地化(首字母大寫)
- (NSString *)capitalizedStringWithLocale:(nullable NSLocale *)locale; 

   //////////分行//////////
//1.指定範圍,分行取字符串
- (void)getLineStart:(nullable NSUInteger *)startPtr end:(nullable NSUInteger *)lineEndPtr contentsEnd:(nullable NSUInteger *)contentsEndPtr forRange:(NSRange)range;
//2.獲取指定範圍該行的範圍
- (NSRange)lineRangeForRange:(NSRange)range;

   //////////分段//////////
//3.指定範圍,分段取字符串
- (void)getParagraphStart:(nullable NSUInteger *)startPtr end:(nullable NSUInteger *)parEndPtr contentsEnd:(nullable NSUInteger *)contentsEndPtr forRange:(NSRange)range;
//4.獲取指定範圍該段落的範圍
- (NSRange)paragraphRangeForRange:(NSRange)range;

  //////////字符串分行,分段//////////
    NSString *string = @"123 456\nABC,DEF\nabc.def";
    //獲取該行的範圍(指定範圍)
    NSRange range1 = [string lineRangeForRange:NSMakeRange(0, 10)];
    NSLog(@"%ld 行長度:     %ld", range1.location, range1.length);
    //輸出:       0 行長度:     16

    //獲取該段落範圍(指定範圍)
    NSRange range2 = [string paragraphRangeForRange:NSMakeRange(0, 3)];
    NSLog(@"%ld 段落長度:   %ld", range2.location, range2.length);
    //輸出:       0 段落長度:   8

   //////////字符串列舉//////////    
   NSString *string = @"123456\nABCDEF\nabcdef
    //1.列舉(按行)
   [string enumerateLinesUsingBlock:^(NSString * _Nonnull line, BOOL * _Nonnull stop) {
       NSLog(@"每行:   %@", line);
   }];
    //輸出:    每行:   123456
    //輸出:    每行:   ABCDEF
    //輸出:    每行:   abcdef
    
 
    //2.列舉(範圍,條件)
    [string enumerateSubstringsInRange:NSMakeRange(5, 10) options:NSStringEnumerationByLines usingBlock:^(NSString * _Nullable substring, NSRange substringRange, NSRange enclosingRange, BOOL * _Nonnull stop) {
       
        NSLog(@"%@", substring);
        NSLog(@"%ld   %ld", substringRange.location, substringRange.length);
        NSLog(@"%ld   %ld", enclosingRange.location, enclosingRange.length);
        
    }];
    //輸出:   6
    //輸出:   5 1
    //輸出:   5 2
    
    //輸出:   ABCDEF
    //輸出:   7   6
    //輸出:   7   7
    
    //輸出:   a
    //輸出:   14   1
    //輸出:   14   1

    //////////字符串分割//////////
    NSString *string = @"A_B_c_D_E_F";
    
    //分割(指定字符串)
    NSArray *resultArr1 = [string componentsSeparatedByString:@"_"];
    NSLog(@"%@", resultArr1);
    //輸出:   (A, B, c, D, E, F)

    //分割(指定字符集合)
    NSArray *resultArr2 = [string componentsSeparatedByCharactersInSet:[NSCharacterSet lowercaseLetterCharacterSet]];
    NSLog(@"%@", resultArr2);    
    //輸出:   ("A_B_" , "_D_E_F")

    //////////字符串翻譯//////////
    NSString *dalian = @"大連";
    NSString *result = [dalian stringByApplyingTransform:NSStringTransformMandarinToLatin reverse:NO];
    
    NSLog(@"%@", result);
    //輸出:   dà lián

   //////////字符串寫入//////////
    //寫入到指定路徑,編碼的文件中
    [string writeToFile:@"/Users/Desktop/LuisX.txt" atomically:YES encoding:NSUTF8StringEncoding error:nil];
    
    //寫入到指定URL,編碼的文件中
    [string writeToURL:[NSURL URLWithString:@"file://LuisX.text"] atomically:YES encoding:NSUTF8StringEncoding error:nil];

//////////字符串分配容量//////////
    
   //1.初始化容量為Capacity大小的字符串  (需要手動釋放內存)
   NSMutableString *mutableStr1 = [[NSMutableString alloc] initWithCapacity:20];
    
   //2.初始化容量為Capacity大小的字符串  (不需要手動釋放內存)
   NSMutableString *mutableStr2 = [NSMutableString stringWithCapacity:20];

   NSMutableString *str = [NSMutableString stringWithString:@"string"];
    
    //////////插入//////////
    [str insertString:@"123" atIndex:2];
    NSLog(@"%@", str);
    //輸出:   st123ring
    
    
    //////////刪除//////////
    [str deleteCharactersInRange:NSMakeRange(2, 2)];
    NSLog(@"%@", str);
    //輸出:   st3ring
    
    
    //////////拼接//////////
    [str appendString:@"456"];
    NSLog(@"%@", str);
    //輸出:   st3ring456
    
    
    //////////格式化拼接//////////
    [str appendFormat:@"7 89"];
    NSLog(@"%@", str);
    //輸出:   st3ring4567 89
    
    
    //////////設置新字符串//////////
    [str setString:@"string"];
    NSLog(@"%@", str);
    //輸出:   string

    //////////字符串替換//////////
    //1.指定範圍替換
    [str1 replaceCharactersInRange:NSMakeRange(2, 2) withString:@"123"];
    NSLog(@"%@", str1);
    //輸出:   st123ng
    
    
    //2.指定字符串,條件,範圍替換
    [str1 replaceOccurrencesOfString:@"123" withString:@"--" options:NSRegularExpressionSearch range:NSMakeRange(0, str1.length)];
    NSLog(@"%@", str1);
    //輸出:   st--ng