Unsigned Char Array to Hex Representation NSString

Question

I have an unsigned char array and I want to convert it to hex NSString, currently I do it in the following way:

unsigned char result[16];
// Fill the array

NSString *myHexString = [NSString stringWithFormat: @"%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X",
    result[0], result[1], result[2], result[3], 
    result[4], result[5], result[6], result[7],
    result[8], result[9], result[10], result[11],
    result[12], result[13], result[14], result[15]
]];

Is there a ~~better way to~~ built-in function that achieves that?

zoul · Accepted Answer · 2011-05-12 12:16:33Z

10

How about this?

NSMutableString *hex = [NSMutableString string];
for (int i=0; i<16; i++)
    [hex appendFormat:@"%02x", result[i]];

// And if you insist on having the hex in an immutable string:
NSString *immutableHex = [NSString stringWithString:hex];

You can also turn the code into a category to keep things nice:

@implementation NSString (Hex)

+ (NSString*) hexStringWithData: (unsigned char*) data ofLength: (NSUInteger) len
{
    NSMutableString *tmp = [NSMutableString string];
    for (NSUInteger i=0; i<len; i++)
        [tmp appendFormat:@"%02x", data[i]];
    return [NSString stringWithString:tmp];
}

@end

Then your code boils down to:

unsigned char result[16] = {…};
NSString *hexString = [NSString hexStringWithData:result ofLength:16];

I think that’s about as nice as it gets.

edited May 12, 2011 at 12:16

answered May 12, 2011 at 12:05

zoul

105k44 gold badges265 silver badges365 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

MByD Over a year ago

thanks, but that's not what I mean, especially because I will need to convert it to NSString right after. I want to know if there's a built in function.

zoul Over a year ago

NSMutableString descends from NSString, so that you can use it wherever an NSString is needed. If you really want to, you can easily create an immutable string from the mutable one, I have edited the answer to add an example. I don’t think there’s a built-in function to do this.

MByD Over a year ago

thanks for the update, I was just wondering if there's a built in function for that. Seems like the answer is no, but you did make it nice enough :)

kraag22 Over a year ago

NSString doesn't have method hexStringWithData. You have to use NSData initWithBytes

Collectives™ on Stack Overflow

Unsigned Char Array to Hex Representation NSString

1 Answer 1

4 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related