如何使用 Objective-C 解析日期字符串

Question

How can i parse an NSString who who have this form "2011052620110529" to get each value as a NSString? i tried to write this

NSDateFormatter *formatter = [[[NSDateFormatter alloc] init] autorelease];
[formatter setDateFormat:@"yyyyMMddyyyyMMdd"];

but i don't think it's correct... Help me please

Answer 1

(I'm assuming here you mean "parse it into dates", not "parse it into two strings." Your question is not clear.)

That string doesn't represent a single valid moment in time; rather, it represents (presumably) a range of time.

You'll have to split the string in two before parsing the two dates, then get the interval between them. Assuming each component is always 8 characters long:

NSString *strComplete = ...;
NSString *strFirstDate = [strComplete substringToIndex: 8];
NSString *strSecondDate = [strComplete substringFromIndex: 8];

NSDateFormatter *formatter = [[[NSDateFormatter alloc] init] autorelease];
[formatter setDateFormat:@"yyyyMMdd"];
NSDate *firstDate = [formatter dateFromString: strFirstDate];
NSDate *secondDate = [formatter dateFromString: strSecondDate];

NSTimeInterval timeInterval = [secondDate timeIntervalSinceDate: firstDate];

Answer 2

you want to parse the number or what? You're sentences are heard to read..

Take a look at NSString's class reference , its fairly easy to break a string up in more parts.

[yourString subStringWithRange:NSMakeRange(location,length)];

Answer 3

Your NSString value contains 2 dates, not one. So you won't be able to use NSDateFormatter to parse it in one step. You'll need to parse each date separately by first extracting the first 8 characters, then the last 8, using something like [s substringWithRange:NSMakeRange(0,8)] and [s substringWithRange:NSMakeRange(8,8)] . Then you can pass these sub-strings into a date formatter using a format like "yyyyMMdd".