nsstring

Is there any method in Objective-C that converts a hex string to bytes? For example @"1156FFCD3430AA22" to an unsigned char array {0x11, 0x56, 0xFF, ...} . Fastest NSString category implementation that I could think of (cocktail of some examples): - (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

I've currently got a webserver set up which I communicate over SOAP with my iPhone app. I am returning a string containing a GUID and when I attempt to compare this with another string I get some strange results. Why would this not fire? Surely the two strings are a match? NSString *myString = @"hello world"; if(myString == @"hello world") return; Use the -isEqualToString: method to compare the value of two strings. Using the C == operator will simply compare the addresses of the objects. if ([category isEqualToString:@"Some String"]) { // Do stuff... } mxg You can use case-sensitive or case

How do I test if an NSString is empty in Objective-C? Marc Charbonneau You can check if [string length] == 0 . This will check if it's a valid but empty string (@"") as well as if it's nil, since calling length on nil will also return 0. Matt G Marc's answer is correct. But I'll take this opportunity to include a pointer to Wil Shipley's generalized isEmpty , which he shared on his blog : static inline BOOL IsEmpty(id thing) { return thing == nil || ([thing respondsToSelector:@selector(length)] && [(NSData *)thing length] == 0) || ([thing respondsToSelector:@selector(count)] && [(NSArray *

I have been googling so much on how to do this, but how would I reverse a NSString? Ex:hi would become: ih I am looking for the easiest way to do this. Thanks! @Vince I made this method: - (IBAction)doneKeyboard { // first retrieve the text of textField1 NSString *myString = field1.text; NSMutableString *reversedString = [NSMutableString string]; NSUInteger charIndex = 0; while(myString && charIndex < [myString length]) { NSRange subStrRange = NSMakeRange(charIndex, 1); [reversedString appendString:[myString substringWithRange:subStrRange]]; charIndex++; } // reversedString is reversed, or