日期转星期几

NSArray *arrWeek=[NSArray arrayWithObjects:@"周日", @"周一", @"周二", @"周三", @"周四", @"周五", @"周六", nil];

NSDate *date = [NSDate date];

NSCalendar *calendar = [ [NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

NSDateComponents *comps = [[NSDateComponents alloc] init];

NSInteger unitFlags = NSYearCalendarUnit |

NSMonthCalendarUnit |

NSDayCalendarUnit |

NSWeekdayCalendarUnit |

NSHourCalendarUnit |

NSMinuteCalendarUnit |

NSSecondCalendarUnit;

comps = [calendar components:unitFlags fromDate:date];

int week = [comps weekday];

int a = week - 1;

NSString *weekStr = [NSString stringWithFormat:@"%@",[arrWeek objectAtIndex:a]];

NSLog(@"啦啦啦 %@",weekStr);