从NSData转换为NSString后更改了字符串信息

Question

I'm converting a NSData object, that is returned from AFHTTPRequestOperation, to NSString:

NSString *responseString = [[NSString alloc] initWithData:responseObject
                             encoding:NSUTF8StringEncoding];
NSLog(@"%@", responseString);

but I realised that the information in responseObject is changed from

<39306563 34636638 30353164 34303365 66346531 38643265 37393036 63333866>

to

90ec4cf8051d403ef4e18d2e7906c38f

Help me please...

Answer 1

There is no change of the data, they are two different representations of the same data: hexadecimal and character (ASCII).

39306563 34636638 30353164 34303365 66346531 38643265 37393036 63333866
Is a hexadecimal representation of the data.

90ec4cf8051d403ef4e18d2e7906c38f
Is a character string representation.

They are the same data.

As a partial example: In the hexadecimal example each two character represents one byte as two hexadecimal digits.
In the character example each character represents one byte as one character.

hex 39 is character 9
hex 30 is character 0
hex 65 is character e
hex 63 is character c
...