Kotlin有一个很好的特性，叫做字符串模板。

val i = 10 
val s = "i = $i" // evaluates to "i = 10"

但是可以在模板中设置格式吗?例如，我想在kotlin中格式化Double in字符串模板，至少要在小数分隔符后设置一些数字:

val pi = 3.14159265358979323
val s = "pi = $pi??" // How to make it "pi = 3.14"?

javascript中是否有类似于Python的zip函数?也就是说，给定多个相等长度的数组，创建一个由对组成的数组。

例如，如果我有三个这样的数组:

var array1 = [1, 2, 3];
var array2 = ['a','b','c'];
var array3 = [4, 5, 6];

输出数组应该是:

var outputArray = [[1,'a',4], [2,'b',5], [3,'c',6]]

我的代码在普通设备上工作正常，但在视网膜设备上产生模糊的图像。

有人知道我的问题的解决方案吗?

+ (UIImage *) imageWithView:(UIView *)view
{
    UIGraphicsBeginImageContext(view.bounds.size);
    [view.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage * img = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return img;
}

我有一个数字，我需要转换成一个字符串。首先我用了这个:

Key = i.ToString();

但我意识到它的排序顺序很奇怪所以我需要用0填充它。我怎么能这样做呢?

如何将datetime对象格式化为带有毫秒的字符串?

我想要显示:

49 as 49.00

and:

54.9和54.90

无论小数点的长度或是否有任何小数点，我想显示一个小数点后2位的小数，我想以一种有效的方式做到这一点。目的是展示货币价值。

例如,4898489.00

有关内置浮点类型的类似问题，请参阅将浮点数限制为两个小数点。

让我们来:

l = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]

我想要的结果是

r = [[1, 4, 7], [2, 5, 8], [3, 6, 9]]

而不是

r = [(1, 4, 7), (2, 5, 8), (3, 6, 9)]

我有一个价格字段显示，有时可以是100或100.99或100.9，我想要的是显示价格在小数点后2位，只有小数输入的价格，例如，如果它的100，它应该只显示100而不是100.00，如果价格是100.2，它应该显示100.20类似的100.22应该是一样的。 我谷歌了一下，找到了一些例子，但它们并不完全符合我想要的:

// just two decimal places
String.Format("{0:0.00}", 123.4567);      // "123.46"
String.Format("{0:0.00}", 123.4);         // "123.40"
String.Format("{0:0.00}", 123.0);         // "123.00"

C # 2008

我已经在这方面工作了一段时间，但我仍然对在代码中使用finalize和dispose方法感到困惑。我的问题如下:

I know that we only need a finalizer while disposing unmanaged resources. However, if there are managed resources that make calls to unmanaged resources, would it still need to implement a finalizer? However, if I develop a class that doesn't use any unmanaged resource - directly or indirectly, should I implement the IDisposable to allow the clients of that class to use the 'using statement'? Would it be feasible to implement IDisposable just to enable clients of your class to use the using statement? using(myClass objClass = new myClass()) { // Do stuff here } I have developed this simple code below to demonstrate the Finalize/dispose use: public class NoGateway : IDisposable { private WebClient wc = null; public NoGateway() { wc = new WebClient(); wc.DownloadStringCompleted += wc_DownloadStringCompleted; } // Start the Async call to find if NoGateway is true or false public void NoGatewayStatus() { // Start the Async's download // Do other work here wc.DownloadStringAsync(new Uri(www.xxxx.xxx)); } private void wc_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e) { // Do work here } // Dispose of the NoGateway object public void Dispose() { wc.DownloadStringCompleted -= wc_DownloadStringCompleted; wc.Dispose(); GC.SuppressFinalize(this); } }

关于源代码的问题:

Here I have not added the finalizer, and normally the finalizer will be called by the GC, and the finalizer will call the Dispose. As I don't have the finalizer, when do I call the Dispose method? Is it the client of the class that has to call it? So my class in the example is called NoGateway and the client could use and dispose of the class like this: using(NoGateway objNoGateway = new NoGateway()) { // Do stuff here } Would the Dispose method be automatically called when execution reaches the end of the using block, or does the client have to manually call the dispose method? i.e. NoGateway objNoGateway = new NoGateway(); // Do stuff with object objNoGateway.Dispose(); // finished with it I am using the WebClient class in my NoGateway class. Because WebClient implements the IDisposable interface, does this mean that WebClient indirectly uses unmanaged resources? Is there a hard and fast rule to follow this? How do I know that a class uses unmanaged resources?

我需要将前导零添加到整数，使一个具有定义数量的数字($cnt)的字符串。 把这个简单的函数从PHP翻译成Python的最好方法是什么:

function add_nulls($int, $cnt=2) {
    $int = intval($int);
    for($i=0; $i<($cnt-strlen($int)); $i++)
        $nulls .= '0';
    return $nulls.$int;
}

有没有函数可以做到这一点?