Question

NSMutableArray *myIdentityArray = [[NSMutableArray alloc]initWithObjects:@"3",@"1", @"2",@"0", @"0", @"1",@"3",@"1", @"2",@"0", @"0", @"1", nil];

现在如何使用具有对象1的所有索引创建一个Array1。对于这种情况，它将有1,5,7和11作为其元素？

Answer 1

您必须使用if条件来检查每个对象的值，然后将对象的索引存储在数组中。

请参阅：Search NSArray for value matching value

Answer 2

您可以在NSMutableArray

上使用indexOfObject：inRange：方法

检查此代码：

   NSMutableArray *myIdentityArray = [[NSMutableArray alloc]initWithObjects:@"3",@"1", @"2",@"0", @"0", @"1",@"3",@"1", @"2",@"0", @"0", @"1", nil];
    NSMutableArray * array1 = [NSMutableArray array];

    NSUInteger loc = 0;
    NSUInteger len = myIdentityArray.count;

    NSRange range = NSMakeRange(loc, len);
    NSUInteger idx = [myIdentityArray indexOfObject:@"1" inRange:range];

    while (idx != NSNotFound) {
        [array1 addObject:[NSNumber numberWithUnsignedInteger:idx]];
        loc = idx +1;
        len = myIdentityArray.count - loc;
        range = NSMakeRange(loc, len);
        idx = [myIdentityArray indexOfObject:@"1" inRange:range];
    }

    NSLog(@"%@",array1);

Answer 3

通过简单的循环执行此操作：

NSMutableArray *myIdentityArray = @[ @"3", @"1", @"2", @"0", @"0", @"1", @"3", @"1", @"2", @"0", @"0", @"1" ];
NSString *search = @"1";

NSMutableArray *results = [NSMutableArray array];

NSInteger index = 0;
for (NSString *str in myIdentityArray) {
    if ([str isEqualToString:search]) {
        [results addObject:@(index)];
    }
    index++;
}

NSLog(@"results = %@", results);

如何从包含我选择的对象的数组创建索引数组？

3 个答案: