時間戳

時間戳
//NSDate 時間差
NSDate *date = [NSDate date];

//從1970年到當前時間全部的秒數
NSTimeInterval timeSecondes = [date timeIntervalSince1970];
NSLog("%f",[date timeIntervalSinceNow]);
NSLog("%f",timeSecondes);

//定義特定的日期
NSTimeInterval yestedaySeconds = 24*60*60;

//昨天的日期
NSDate *yesterDate = [NSDate dateWithTimeIntervalSinceNow:-yestedaySeconds];
NSLog("%",yesterDate);

//兩個日期的時間差
NSTimeInterval betweenSenconds = [yesterDate timeIntervalSinceDate:myDate];
NSLog(@"%f",betweenSenconds);