Question

我试图将范围（0到9）中的所有数字相加，可以除以3或5。

方法1：

result

打印23，这是预期的。

方法2：与上述相同。但我试图忽略临时变量println (0..9).findAll { (it % 3 == 0 || it % 5 == 0) }.sum()＆amp;直接打印。

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

打印def lst = 0..9 println lst.findAll { (it % 3 == 0 || it % 5 == 0) }.sum()

这里发生了什么？为什么显示整个列表而不是方法2中的总和。

方法3：与方法相同2.直接打印。但是将范围移动到变量。

public class Send {

public static void main(String[] args) throws Exception {
    Socket socket = new Socket("localhost", 13085);
    OutputStream outputStream = socket.getOutputStream();

    BufferedImage image = ImageIO.read(new File("C:\\Users\\Jakub\\Pictures\\test.jpg"));

    ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
    ImageIO.write(image, "jpg", byteArrayOutputStream);

    byte[] size = ByteBuffer.allocate(4).putInt(byteArrayOutputStream.size()).array();
    outputStream.write(size);
    outputStream.write(byteArrayOutputStream.toByteArray());
    outputStream.flush();
    System.out.println("Flushed: " + System.currentTimeMillis());

    Thread.sleep(120000);
    System.out.println("Closing: " + System.currentTimeMillis());
    socket.close();
}
}


public class Receive {

public static void main(String[] args) throws Exception {
    ServerSocket serverSocket = new ServerSocket(13085);
    Socket socket = serverSocket.accept();
    InputStream inputStream = socket.getInputStream();

    System.out.println("Reading: " + System.currentTimeMillis());

    byte[] sizeAr = new byte[4];
    inputStream.read(sizeAr);
    int size = ByteBuffer.wrap(sizeAr).asIntBuffer().get();

    byte[] imageAr = new byte[size];
    inputStream.read(imageAr);

    BufferedImage image = ImageIO.read(new ByteArrayInputStream(imageAr));

    System.out.println("Received " + image.getHeight() + "x" + image.getWidth() + ": " + System.currentTimeMillis());
    ImageIO.write(image, "jpg", new File("C:\\Users\\Jakub\\Pictures\\test2.jpg"));

    serverSocket.close();
}
}

再次打印23。

Groovy是否希望我总是有一个临时变量:( ??

Answer 1

groovy解析器认为你正在做

println (0..9)

然后将其余部分用于println的结果

只需给解析器一个外围的括号

println( (0..9).findAll {
    (it % 3 == 0 || it % 5 == 0)
}.sum() )

Groovy - 列出总和

1 个答案: