Question

我正在研究这个for循环并且它工作得很完美..我经常返回找到的数字列表，但是我需要for循环让我按降序返回数字...从30到18而不是现在18-30岁......有人可以帮我一个忙吗？

我发布了有问题的代码

  for (NSInteger i = 18; i <= 30; i += 2) {


    self.axisY_Label = [[UILabel alloc] initWithFrame:CGRectMake(10, paddingValue, 35, 20)];
    self.axisY_Label.text = [NSString stringWithFormat:@"%ld", (long)i];
    self.axisY_Label.textColor = [UIColor whiteColor];
    self.axisY_Label.font = [UIFont fontWithName:@"HelveticaNeue" size:13];


    UIView *line = [[UIView alloc] initWithFrame:CGRectMake(_axisY_Label.frame.size.width, _axisY_Label.center.y, self.frame.size.width, 0.3)];
    line.backgroundColor = [UIColor whiteColor];
    line.alpha = .2;
    [self addSubview:line];

    paddingValue += _axisY_Label.frame.size.width;
    [self addSubview:_axisY_Label];

}

Answer 1

交换from和to参数并向后计数

for (NSInteger i = 30; i >= 18; i -= 2) { ...

在循环中反转NSInteger

1 个答案: