C# 数字 String Format $ 语法

reference: https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/tokens/interpolated

// 5表示最小宽度(包含小数点,正负号)
// 0.0 表示显示的精度
 var d1 = 1.2345;
 var d2 = -5.425151;
 var d3 = 1234567.89
 var s1 = $"{d1,5:0.0}";
 var s2 = $"{d2,5:0.0}";
 var s3 = $"{d2,5:###,###}"; // 1234,567   

问号表达式必须以括号包含

string name = "Horace";
int age = 34;
Console.WriteLine($"He asked, \"Is your name {name}?\", but didn't wait for a reply :-{{");
Console.WriteLine($"{name} is {age} year{(age == 1 ? "" : "s")} old.");
// Expected output is:
// He asked, "Is your name Horace?", but didn't wait for a reply :-{
// Horace is 34 years old.