Converting NSData to NSString without knowing the encoding type

Question

Disclaimer:

• this previous question does not contain a valid answer.
• this other instead does contain the technique I used to convert it but does not answer the question I have.

Question:

I am reading some NSData from a BLE characteristic which corresponds to a string , however I have no idea what encoding format it uses.

This is the view from the debugger on Xcode:

How can I convert it to a string? I'd like to extract this value: "<951c7c1d e0fbdcc3 7b8b0b97 5c522036>"

I tried the following with with no meanigful conversion. However XCode seems to do the job. Why?

NSData * valueAsData = characteristic.value.mutableCopy;

NSString* newStr = [[NSString alloc] initWithData:characteristic.value encoding:NSUTF8StringEncoding];
NSString* newStr2 = [[NSString alloc] initWithData:characteristic.value encoding:NSASCIIStringEncoding];

Answer 1

Get the descriptors associated with the characteristic. One of them should be CBUUIDCharacteristicFormatString . This will indicate the presentation format , which will indicate the data type of the characteristic value.