空值合并运算符(Null Coalescing Operator ??)空值合并运算符提供了一种简洁的方式来处理可能为空的变量。C# 全选 string name = null; string RegName = name ?? "csframework.com"; Console.WriteLine(RegName);//输出"csframework.com" 专注.NET技术、C/S架构开发框架软件 C/S框架网 - C/S开发框架 ...
-1; Listing 2-47Using a null-coalescing operator 多时髦啊。我们的代码已经减少到两行代码,它做的事情与清单 2-46 中的完全一样。有了 C# 7.0,我们现在也能使用模式匹配了。因此,我们可以做到以下几点。 int iValue = 10; int? iValue2 = null; if (iValue2 is int value) { iValue = value; }...
有了可选链式调用 ,可以大量简化类似繁琐的前置校验操作,而且更安全: let nestedProp = obj?.first?.second; 1. 如果obj或obj.first是null/undefined,表达式将会短路计算直接返回undefined。 可选链操作符的支持情况: 空位合并操作符(Nullish coalescing Operator) 当我们查询某个属性时,经常会给没有该属性就设置一...
privatestaticvoidNullCoalescingOperator() { Int32? b =null;//x = (b.HasValue) ? b.Value : 123Int32 x = b ??123; Console.WriteLine(x);//"123"//String temp = GetFilename();//filename = (temp != null) ? temp : "Untitled";String filename = GetFilename() ??"Untitled"; } ...
空值合并运算符(Nullish coalescing Operator) 空值合并操作符( ?? )是一个逻辑操作符,当左侧的操作数为 null或者undefined时,返回其右侧操作数,否则返回左侧操作数。 const foo = undefined ?? "foo" const bar = null ?? "bar" console.log(foo) // foo console.log(bar) // bar 1. 2. 3. 4. 与...
string { // null coalescing operator return $this->configuration[$key] ?? null; } } Load configuration and create instance of Configuration class $configuration = new Configuration([ 'foo' => 'bar', ]); And now you must use instance of Configuration in your application. ⬆ back to top...
单层HDR图片转换双层 调用者可以调用本模块提供的C API接口,实现Decompose单层HDR图片转双层HDR图片。 该能力常用于图片分享中,如下图所示: 规格说明支持的数据输入格式: 使用……欲了解更多信息欢迎访问华为HarmonyOS开发者官网
- Use the [null-coalescing operator](../../language-reference/operators/null-coalescing-operator.md), `??`, to assign a value to an underlying type based on a value of the nullable type: `int? x = null; int y = x ?? -1;`. In the example, since `x` is null, the result va...
2 Developing and Porting C and C++ Applications on AIX In addition to the usual optimizations performed by the optimizer, IPA also performs many optimizations interprocedurally, including: Inlining across compilation units Program partitioning Global variables coalescing Code straightening Dead code ...
7.12 The null coalescing operator 201 7.13 Conditional operator 202 7.14 Anonymous function expressions 203 7.14.1 Anonymous function signatures 205 7.14.2 Anonymous function bodies 205 7.14.3 Overload resolution 206 7.14.4 Outer variables 206