Objective-C parse hex string to integer

Solution 1:

Joshua Weinberg's answer is mostly correct, however the 0x prefix is optional when scanning hexadecimal integers. If you have a string in the format #01FFFFAB, you can still use NSScanner, but you can skip the first character.

unsigned result = 0;
NSScanner *scanner = [NSScanner scannerWithString:@"#01FFFFAB"];

[scanner setScanLocation:1]; // bypass '#' character
[scanner scanHexInt:&result];

Solution 2:

you can use NSScanner for this

unsigned int outVal;
NSScanner* scanner = [NSScanner scannerWithString:@"0x01FFFFAB"];
[scanner scanHexInt:&outVal];

outVal will contain the int you're looking for. The 0x is optional.

Solution 3:

strtol() is your friend.

It converts a string to a long, and you can pass the base of the number in. Strip that # sign off first though, or pass to strtol a pointer to the first numerical character.

Solution 4:

You can use the below line for conversion. Its just one line code:

NSString *hexString = @"01FFFFAB";
length = (UInt64)strtoull([hexString UTF8String], NULL, 16);
NSLog(@"The required Length is %d", length);

Happy Coding!!!

Solution 5:

Swift 4 standard library introduced new initializer for parsing all integer types. It takes string to parse with radix (i.e. base) and returns optional integer:

let number = Int("01FFFFAB", radix: 16)!