String interpolation

C# language feature:

String interpolation

applies to

formatting of strings

benefit

Allows writing of string formatting expressions using inline expressions instead of positional arguments. Improves code readability.

how to use

Prefix interpolated string with $ and replace position index with interpolated expression. Argument list is no longer needed.

note

Any valid C# expression is allowed inside the { } characters in an interpolated string which includes and is not limited to computations, conditionals, method calls, and LINQ queries. Interpolated string syntax is $"<text> {<interpolated-expression> [,<field-width>] [:<format-string>] } <text> ..."

example:

        class String_interpolation_Example
        {
            public void Use_of_String_interpolation()
            {
                var name = "Jeff";
                Console.WriteLine($"Hello, {name}!");   // note $ prefix used to denote embedded inline code.
                // old way i.e. composite string formatting
                Console.WriteLine("Hello, {0}!", name);  // note the argument 'name' is not needed for string interpolation
            }

        }

C# articles

csharp v2 +

Anonymous methods * Co- and Contra-variance for delegates * Delegate inference * Generics * Getter and setter separate accessibility * Iterators * Method group conversions (delegates) * Nullable types * Partials * Static classes *

csharp v3 +

Anonymous types * Auto-Implemented properties * Expression trees * Extension methods * Implicitly typed local variables * Lambda expression * Object and collection initializers * Partial methods * Query expressions *

csharp v4 +

Generic co- and contravariance * Named and optional arguments *

csharp v5 +

Asynchronous methods * Caller info attributes *

csharp v6 +

A note for CSharp 6 and beyond * Allow await in catch and finally blocks * Auto property initializers * Default values for Read-only Auto-properties * Dictionary (index) initializers * Exception filters * Expression-bodied members * Import of static type members into namespace * Null propagator (null-conditional operator, succinct null checking) * String interpolation * nameof operator *

csharp v7 +

Binary literals * Deconstruction * Digit separators * Expression bodied constructors and finalizers * Expression bodied getters and setters * Generalized async return types * Local functions * Out variables * Pattern matching * Ref returns and locals * Tuples *

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