Question

使用字典将一个值添加到NSMutableArray中 SelectedDate =“2016-08-12”;

我正在尝试从MutableArray中获取日期，

   NSDate *dateFromTable = [[Array valueForKey:@"SelectedDate"] objectAtIndex:0];
            NSDateFormatter *dateformate=[[NSDateFormatter alloc]init];
            [dateformate setDateFormat:@"dd"];
       NSString   *dateValue = [dateformate stringFromDate:dateFromTable];

dateValue总是返回nil，不知道我做错了什么。

Answer 1

根据您的代码进行调整：

NSArray *array = @[@"2016-08-12"]; // array with dates in string format
NSString *dateFromTable = array.firstObject; // get first element
NSDateFormatter *dateformater =[NSDateFormatter new];
[dateformater setDateFormat:@"yyyy-MM-dd"];
NSDate *date = [dateformater dateFromString:dateFromTable]; // get date from string
NSLog(@"%@", date); // 2016-08-12 22:00:00 +0000
[dateformater setDateFormat:@"dd"];
NSString *dateValue = [dateformater stringFromDate:date]; // get string from date
NSLog(@"%@", dateValue); // 12

Answer 2

从数组获取日期到字符串并转换为日期

var

然后，如果您想将日期转换为字符串，请按照以下步骤进行操作

NSString *dateFromTable = [NSString stringWithFormat:@"%@",[[Array valueForKey:@"SelectedDate"] objectAtIndex:0]];
NSDateFormatter *dateformate=[[NSDateFormatter alloc]init];
[dateformate setDateFormat:@"yyyy-MM-dd"];
NSDate   *dateValue = [dateformate dateFromString:dateFromTable];

日期值为零

2 个答案: