I have an exact string as say "November 4, 2010" and I want to compare it with today's date in iPhone?

How can one convert开发者_如何转开发 a string "November 4, 2010" and not "MMMM d, YYYY" to NSDate for comparison?

You can use a NSDateFormatter, for this behaviour.

eg.

NSString *string = @"November 4, 2010";
[NSDateFormatter setDefaultFormatterBehavior:NSDateFormatterBehavior10_0];
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
formatter.dateFormat = @"%B %e, %j";
NSDate *wantedDate = [formatter dateFromString:string];


[[Date date] compareWithDate:wantedDate]; // will return basically, what you want

See the NSDateFormatter class reference, and the Data Formatting Guide. For background information about date formatting see: here.