Scala | 懶惰的瓦爾 (Scala | lazy val)

Scala programming language allows the user to initialize a variable as a lazy val. A lazy variable is used when we need to save memory overheads while object creation. Using the lazy keyword, you can halt the initialization of the variable until the time it is first used or accessed in the code.

Scala編程語言允許用戶將變量初始化為惰性val 。 當我們需要在創建對象時節省內存開銷時，可以使用惰性變量 。 使用lazy關鍵字，可以暫停變量的初始化，直到在代碼中首次使用或訪問該變量為止。

程序來說明懶惰的瓦爾 (Program to illustrate lazy val)

object myObject { def main(args:Array[String]) { lazy val newBlock = { println ("This will be printed only in case of first initialization.") "Hello!"} println("The block is not initialized yet!")println("First Call : ")println(newBlock)println("Second Call : ")println(newBlock) } }

Output

輸出量

The block is not initialized yet! First Call : This will be printed only in case of first initialization. Hello! Second Call : Hello!

As in the code, the block is initialized after the first print statement when it is called. The print statement of the newBlock will be printed only once. In the second call, it will return the string "Hello!" and does not print anything.

與代碼中一樣，該塊在調用第一個print語句之后初始化。 newBlock的打印語句將僅打印一次。 在第二個調用中，它將返回字符串“ Hello！”。 并且不打印任何內容。

翻譯自: https://www.includehelp.com/scala/lazy-val.aspx

總結

以上是生活随笔為你收集整理的Scala懒惰瓦尔的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。