帮助分组数组索引 (objectAtIndex 0 - 9) = 1 个索引点

Question

我正在尝试创建一个多项选择测试应用程序。我有这段代码来读取 .txt 文件：

filePath = [[NSBundle mainBundle] pathForResource:@"testBank" ofType:@"txt"];
theBank = [[NSString alloc] initWithContentsOfFile:filePath
                                                  encoding:NSUTF8StringEncoding error:NULL];        
multipleChoicePractice = [theBank componentsSeparatedByString:@"\n"];

multipleChoicePractice NSMutableArray 现在包含一堆按以下顺序的 NSString：

 Question 1
 choice A
 choice B
 choice C
 choice D
 Answer Key
 Rationale
 question ID 1
 [string to id type of question]
 [space 1]
 Question 2
 choice A-2 
 etc etc up to Question 10

我试图将每个索引按 10 个一组进行分组，以便 multipleChoicePractice 的索引 0 到 9 是新索引的索引 0可变数组，questionGroupArary。我尝试过：

for (i=0; i<=90; i = i+10) { //qArr being a NSMutableArray
            [qArr addObject:[multipleChoicePractice objectAtIndex:i]];
            [qArr addObject:[multipleChoicePractice objectAtIndex:(i+1)]];
            [qArr addObject:[multipleChoicePractice objectAtIndex:(i+2)]];
            [qArr addObject:[multipleChoicePractice objectAtIndex:(i+3)]];
            [qArr addObject:[multipleChoicePractice objectAtIndex:(i+4)]];
            [qArr addObject:[multipleChoicePractice objectAtIndex:(i+5)]];
            [qArr addObject:[multipleChoicePractice objectAtIndex:(i+6)]];
            [qArr addObject:[multipleChoicePractice objectAtIndex:(i+7)]];
            [qArr addObject:[multipleChoicePractice objectAtIndex:(i+8)]];
            [qArr addObject:[multipleChoicePractice objectAtIndex:(i+9)]];

            [questionGroupArray addObject:qArr];
        }

for 循环的结果是 QuestionGroupArray objectAtIndex: 0 包含问题 1 和问题 10 之间的所有内容。实现我的目标的最佳方法是什么，以便 QuestionGroupArray 索引 0 包含“question1”到“[space 1]”？我觉得有一种方法可以用 for 循环来做到这一点，但我没有想到。谢谢！

Answer 1

在每次迭代中为指针 qArray 创建一个新数组。现在，您只需将同一数组多次添加到 questionGroupArray 中即可。

Answer 2

获取连续范围内的对象子数组的更好方法是使用 -[NSArray subarrayWithRange:]。

// Source is your ungrouped array
NSMutableArray* groups = [NSMutableArray array];
for (int i = ; i < 90; i += 10) {
    NSArray* sub = [source subarrayWithRange:NSMakeRange(i, 10)];
    [groups addObject:sub];
}
// groups is now an array of arrays with your groups.

Answer 3

在循环内创建数组。

for (i=0; i<=90; i = i+10) { //qArr being a NSMutableArray

// Here you have to create a new array for every object
             qArr = [NSMutableArray array];
            [qArr addObject:[multipleChoicePractice objectAtIndex:i]];
            [qArr addObject:[multipleChoicePractice objectAtIndex:(i+1)]];
            [qArr addObject:[multipleChoicePractice objectAtIndex:(i+2)]];
            [qArr addObject:[multipleChoicePractice objectAtIndex:(i+3)]];
            [qArr addObject:[multipleChoicePractice objectAtIndex:(i+4)]];
            [qArr addObject:[multipleChoicePractice objectAtIndex:(i+5)]];
            [qArr addObject:[multipleChoicePractice objectAtIndex:(i+6)]];
            [qArr addObject:[multipleChoicePractice objectAtIndex:(i+7)]];
            [qArr addObject:[multipleChoicePractice objectAtIndex:(i+8)]];
            [qArr addObject:[multipleChoicePractice objectAtIndex:(i+9)]];

            [questionGroupArray addObject:qArr];
        }

另一个优化是有两个 for 循环

for(i=0;i<90;i= i+10)
{
qArr = [NSMutableArray array];
for (j=0;i<10;j++)
{
[qArr addObject:[multipleChoicePractice objectAtIndex:j]];
}
}