根据数组中字典的某一个字段进行排序

首先创建一个包含字典的数组

     NSDictionary * dic = @{@"num":@"1",@"key":@"ewedwedwed"};
    NSDictionary * dic1 = @{@"num":@"4",@"key":@"frfefcerf"};
    NSDictionary * dic2 = @{@"num":@"5",@"key":@"frfwdewdwderf"};
    NSDictionary * dic3 = @{@"num":@"7",@"key":@"frfwdqerf"};
    NSDictionary * dic4 = @{@"num":@"2",@"key":@"defg53y4"};
    NSDictionary * dic5 = @{@"num":@"3",@"key":@"ded"};
    NSMutableArray *arr = [NSMutableArray arrayWithObjects:dic,dic1,dic2,dic4,dic3,dic5, nil];

将用来判断 的字段存储到一个新的数组当中

    NSMutableArray *valArr = [NSMutableArray array];
    for (int i = 0; i < arr.count; i ++) {
        
        NSDictionary *dic = arr[i];
        
        
        NSString * str = [NSString stringWithFormat:@"%@-%d",dic[@"num"],i];
        
        [valArr addObject:str];
        
    }

然后根据索引进行排序

 NSMutableArray *afterValArr = [valArr mutableCopy];
    
    // 根据索引进行依次的排序
    
    for (int  i =0; i<[afterValArr count]-1; i++) {
        
        for (int j = i+1; j<[afterValArr count]; j++) {
            
            NSString *val1 = [afterValArr[i] componentsSeparatedByString:@"-"][0];
            NSString *val2 = [afterValArr[j] componentsSeparatedByString:@"-"][0];
比较两个值的大小，小的在前，大的在后进行交换
            if ([val1 intValue]>[val2 intValue]) {
                //交换
                [afterValArr exchangeObjectAtIndex:i withObjectAtIndex:j];
            }
            
        }
        
    }

最后得到排序好的数组，可以根据情况选择相应的顺序

NSMutableArray *resultArr = [NSMutableArray array];//这个用来存放最后的结果
    //小->大
    for (int i = 0; i < arr.count; i ++) {
        
        NSNumber * val = afterValArr[i];
        NSInteger idx = [valArr indexOfObject:val];
        [resultArr addObject:arr[idx]];
       
    }
    NSLog(@"resArr == %@",resultArr);
    NSLog(@"resArr 0== %@",resultArr[0]);
    NSMutableArray *modelArr = [NSMutableArray array];//存放倒序的数组
    //倒序大->小
    [modelArr addObjectsFromArray:[[resultArr reverseObjectEnumerator]allObjects]];
NSLog(@"modelArr == %@",modelArr);
    NSLog(@"modelArr 0== %@",modelArr[0]);