Convert string to byte array in iOS

Question

I have a string variable in iOS and I would like to convert that to a character array and then to a hex bytes like 0xD6, 0xD6 etc.

It will be great if there is a library in Objective-C that I can use for this

What encoding do you want the bytes? And have you looked at the documentation for `NSString`? There are plenty of methods available depending on what you are actually trying to get. Please [edit] your question with a clear example of what you have and what you want exactly. — rmaddy, May 08 '17 at 21:27

Deepak Tagadiya · Answer 1 · 2019-01-23T05:01:21.397

2

swift 4

 string to byte:

 let strChar = "A" 
 let data1 = [UInt8](self.strChar.utf8)

edited Jan 23 '19 at 05:01

answered Sep 18 '17 at 12:50

Deepak Tagadiya

2,187
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Please add some description rather than just giving a block of code. – Ashley Mills Sep 18 '17 at 13:39
Correction to the above: `let data1 = [UInt8](strChar.utf8)` – Scott McMillin Oct 12 '17 at 20:51
@ScottMcMillin Thanks for suggest. – Deepak Tagadiya Oct 13 '17 at 05:41

score 1 · Accepted Answer · edited May 23 '17 at 12:17

may be answer is here:

string to chars:

NSString *s = @"Some string";
const char *c = [s UTF8String];

chars to hex:

- (NSData *)dataFromHexString {
    const char *chars = [self UTF8String];
    int i = 0, len = self.length;

    NSMutableData *data = [NSMutableData dataWithCapacity:len / 2];
    char byteChars[3] = {'\0','\0','\0'};
    unsigned long wholeByte;

    while (i < len) {
        byteChars[0] = chars[i++];
        byteChars[1] = chars[i++];
        wholeByte = strtoul(byteChars, NULL, 16);
        [data appendBytes:&wholeByte length:1];
    }

    return data;
}

reference:NSString (hex) to bytes

Convert string to byte array in iOS

2 Answers2