Question

这就是我所拥有的：一个NSMutableArray，包含多个NSDictionary个对象。每个NSDictionary都有一个日期字符串作为元素。

这是我的循环，在每个NSDictionary

中打印出日期

[dateFormatterIn setDateFormat:@"yyyyMMddHHmmss\n"];
[dateFormatterOut setDateFormat:@"dd.MM.yyyy"];     

for(NSMutableDictionary *thisStory in stories){
        id fromDate = [thisStory objectForKey:@"from_time"];
        id date = [dateFormatterIn dateFromString:fromDate];
        NSLog(@"%@", [dateFormatterOut stringFromDate:date]);
    }

有没有人知道如何按日期对数组stories进行排序？我对客观C很新。提前谢谢！

Answer 1

使用你的故事数组排序使用描述性方法可以解决这个问题：

NSSortDescriptor *sortDescriptor = [[[NSSortDescriptor alloc] initWithKey: @"from_time" ascending: YES] autorelease];
[stories sortUsingDescriptors: [NSArray arrayWithObject: sortDescriptor]];

Answer 2

让我们假设以下数据结构：数组变量名： collectionArray = [ { date: "01-02-2015 02:01", value: 1, name: "rajan" }, { date: "01-02-2014 02:01", value: 11, name: "rajan1" }, { date: "01-02-2012 02:01", value: 111, name: "rajan2" } ]

现在按日期对nsdictionary数组进行排序，我们按照以下步骤进行操作

`NSDateFormatter * formatter = [[NSDateFormatter alloc] init]; [formatter setDateFormat：@“dd-MM-yyyy HH：mm”];

NSMutableArray *sortedArray = [[collectionArray sortedArrayUsingComparator:^NSComparisonResult(NSDictionary *obj1, NSDictionary *obj2) {

    NSString *d1Str =[obj1 valueForKey:@"date"];
    NSString *d2Str =[obj2 valueForKey:@"date"]

    NSString *d1Timestamp = [NSString stringWithFormat:@"%f", [[formatter dateFromString:d1Str] timeIntervalSince1970]];
    NSString *d2Timestamp = [NSString stringWithFormat:@"%f", [[formatter dateFromString:d2Str] timeIntervalSince1970]];

    return [d2Timestamp compare:d1Timestamp options:NSNumericSearch]; // descending order


}] mutableCopy];`

按包含的NSDictionaries的'Date'元素对NSArray进行排序

2 个答案: