NSString is empty

Question

How do you test if an NSString is empty? or all whitespace or nil? with a single method call?

Answer 1

You can try something like this:

@implementation NSString (JRAdditions)  + (BOOL)isStringEmpty:(NSString *)string {    if([string length] == 0) { //string is empty or nil        return YES;    }      if(![[string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] length]) {        //string is all whitespace        return YES;    }     return NO; }  @end 

Check out the NSString reference on ADC.

Answer 2

This is what I use, an Extension to NSString:

+ (BOOL)isEmptyString:(NSString *)string; // Returns YES if the string is nil or equal to @"" {     // Note that [string length] == 0 can be false when [string isEqualToString:@""] is true, because these are Unicode strings.      if (((NSNull *) string == [NSNull null]) || (string == nil) ) {         return YES;     }     string = [string stringByTrimmingCharactersInSet: [NSCharacterSet whitespaceAndNewlineCharacterSet]];      if ([string isEqualToString:@""]) {         return YES;     }      return NO;   }