ios十进制、十六进制字符串，byte，data等之间的转换

尊重原创精神，此文章为转载，里面的转换帮了我很的大忙，我决定都记录下来方便以后查看，同时我会定期更新工作中遇到的各种转换算法留作记录。

十进制->十六进制

Byte bytes[] = {0xA6,0x27,0x0A};

NSString *strIdL  = [NSString stringWithFormat:@"%@",[[NSString alloc]initWithFormat:@"%02lx",(long)bytes[0]]];

十六进制->十进制

NSString *rechargeInfo =  @"0xff055008";

NSString *cardId2 = [rechargeInfo substringWithRange:NSMakeRange(2,2)];
cardId2 = [NSString stringWithFormat:@"%ld",strtoul([cardId2 UTF8String],0,16)];

NSString *str = @"0xff055008";
//先以16为参数告诉strtoul字符串参数表示16进制数字，然后使用0x%X转为数字类型
unsigned long red = strtoul([str UTF8String],0,16);

//strtoul如果传入的字符开头是“0x”,那么第三个参数是0，也是会转为十六进制的,这样写也可以：

unsigned long red = strtoul([@"0x6587"UTF8String],0,0);
NSLog(@"转换完的数字为：%lx",red);

字符串处理方法

+ (NSString *)cutString:(NSString *)str{
   NSString *targetStr=nil;

   if (str.length>9) {
    targetStr=[str substringFromIndex:9];
   }
   return targetStr;
}

字符串补零操作

+ (NSString *)addZero:(NSString *)str withLength:(int)length{
    NSString *string = nil;
    if (str.length==length) {
      return str;
    }
    if (str.length<length) {
       NSUInteger inter = length-str.length;
    for (int i=0;i< inter; i++) {
        string = [NSString stringWithFormat:@"0%@",str];
        str = string;
    }
    }
    return string;
}

+ (NSString *)stringFromHexString:(NSString *)hexString { 
  char *myBuffer = (char *)malloc((int)[hexString length] / 2 +1);
  bzero(myBuffer, [hexString length] / 2 + 1);
  for (int i =0; i < [hexString length] - 1; i += 2) {
    unsigned int anInt;
    NSString * hexCharStr = [hexString substringWithRange:NSMakeRange(i, 2)];
    NSScanner * scanner = [[NSScanner alloc] initWithString:hexCharStr] ;
    [scanner scanHexInt:&anInt];
    myBuffer[i / 2] = (char)anInt;
    NSLog(@"myBuffer is %c",myBuffer[i /2] );
  }
  NSString *unicodeString = [NSString stringWithCString:myBuffer encoding:4];
  NSLog(@"———字符串=======%@",unicodeString);
  return unicodeString; 
}

10进制->16进制

+ (NSString *)ToHex:(longlong int)tmpid{

   NSString *nLetterValue;
   NSString *str =@"";
   long longint ttmpig;

   for (int i =0; i<9; i++) {
      ttmpig=tmpid%16;
      tmpid=tmpid/16;
      switch (ttmpig)
     {
        case 10:
            nLetterValue =@"A";break;
        case 11:
            nLetterValue =@"B";break;
        case 12:
            nLetterValue =@"C";break;
        case 13:
            nLetterValue =@"D";break;
        case 14:
            nLetterValue =@"E";break;
        case 15:
            nLetterValue =@"F";break;
        default:nLetterValue=[[NSString alloc]initWithFormat:@"%lli",ttmpig];      
    }
    str = [nLetterValue stringByAppendingString:str];
    if (tmpid == 0) {
        break;
    }
   }
    return str;
}

16进制字符串->NSData

+ (NSMutableData *)convertHexStrToData:(NSString *)str {

   if (!str || [str length] == 0) {
     return nil;
   }

   NSMutableData *hexData = [[NSMutableData alloc] initWithCapacity:8];
   NSRange range;

   if ([str length] %2 == 0) {
      range = NSMakeRange(0,2);
   } else {
      range = NSMakeRange(0,1);
   }

   for (NSInteger i = range.location; i < [strlength]; i += 2) {
       unsigned int anInt;
       NSString *hexCharStr = [str substringWithRange:range];
       NSScanner *scanner = [[NSScanner alloc]initWithString:hexCharStr];
    
       [scanner scanHexInt:&anInt];
       NSData *entity = [[NSData alloc]initWithBytes:&anIntlength:1];
       [hexData appendData:entity];
    
       range.location += range.length;
       range.length = 2;
   }
   return hexData;
}

+ (NSString *)convertDataToHexStr:(NSData *)data {
   if (!data || [data length] == 0) {
       return @"";
   }
   NSMutableString *string = [[NSMutableString alloc] initWithCapacity:[data length]];

   [data enumerateByteRangesUsingBlock:^(constvoid *bytes, NSRange byteRange,BOOL *stop) {
       unsigned char *dataBytes = (unsignedchar*)bytes;
       for (NSInteger i =0; i < byteRange.length; i++) {
           NSString *hexStr = [NSString stringWithFormat:@"%x", (dataBytes[i]) &0xff];
           if ([hexStr length] == 2) {
               [string appendString:hexStr];
           } else {
               [string appendFormat:@"0%@", hexStr];
           }
       }
   }];
   return string;
}

十进制->十六进制字符串

+ (NSString *)hexStringFromString:(NSString *)string{

   NSData *myD = [string dataUsingEncoding:NSUTF8StringEncoding];
   Byte *bytes = (Byte *)[myD bytes];

   //下面是Byte转换为16进制。
   NSString *hexStr=@"";

   for(int i=0;i<[myD length];i++){
       NSString *newHexStr = [NSString stringWithFormat:@"%x",bytes[i]&0xff];//16进制数
    
       if([newHexStr length]==1)
        
           hexStr = [NSString stringWithFormat:@"%@0%@",hexStr,newHexStr];
    
       else
        
           hexStr = [NSString stringWithFormat:@"%@%@",hexStr,newHexStr]; 
   } 
   return hexStr; 
}

+ (NSString *) parseByteArray2HexString:(Byte[]) bytes{

   NSMutableString *hexStr = [[NSMutableString alloc]init];

   int i = 0;
   if(bytes){
      while (bytes[i] != '\0')
   {
        NSString *hexByte = [NSString stringWithFormat:@"%x",bytes[i] & 0xff];//16进制数
        if([hexByte length]==1)
            [hexStr appendFormat:@"0%@", hexByte];
        else
            [hexStr appendFormat:@"%@", hexByte];         
        i++;
     }
   }
   NSLog(@"bytes 的16进制数为:%@",hexStr);
   return hexStr;
}