Combine return and switch

Question

How can I combine return and switch case statements?

I want something like

return switch(a)
       {
          case 1:\"lalala         


        

Answer 1

This is the closest I can think of:

return    a==1 ? "lalala"
        : a==2 ? "blalbla"
        : a==3 ? "lolollo"
        : "default";

Answer 2

If you want switch to return value, you can use delegate:

int a = 2;
string result = new Func<string>(delegate ()
{
    switch (a)
    {
        case 1: return "lalala";
        case 2: return "blalbla";
        case 3: return "lolollo";
        default: return "default";
    }
})();

Or:

int a = 2;
string result = new Func<int,string>(delegate (int i)
{
    switch (i)
    {
        case 1: return "lalala";
        case 2: return "blalbla";
        case 3: return "lolollo";
        default: return "default";
    }
})(a);

Or just use lambda:

int a = 2;
string result = new Func<int,string>((int i) =>
{
    switch (i)
    {
        case 1: return "lalala";
        case 2: return "blalbla";
        case 3: return "lolollo";
        default: return "default";
    }
})(a);

Answer 3

Actually this is possible using switch expressions starting with C# 8.

return a switch
    {
        1 => "lalala",
        2 => "blalbla",
        3 => "lolollo",
        _ => "default"
    };

Switch Expressions

There are several syntax improvements here:

• The variable comes before the switch keyword. The different order makes it visually easy to distinguish the switch expression from the switch statement.
• The case and : elements are replaced with =>. It's more concise and intuitive.
• The default case is replaced with a _ discard.
• The bodies are expressions, not statements.

For more information and examples check the Microsoft's C# 8 Whats New.

Answer 4

My mapping solution looks like Jordão's solution but it is more flexible and shorter.

return a
  .Map(1,"lalala")
  .Map(2,"blabla")
  .Map(3,"lololo")
  .Else(string.Empty);

Both arguments can also be a function:

return a
    .Map(x => x <= 0, "lalala")
    .Map(2, "blabla")
    .Map(x => x >= 3, x => "lololo" + x.ToString()); // lololo3 etc.

Answer 5

switch(a)
{
    case 1: return "lalala";
    case 2: return "blalbla";
    case 3: return "lolollo";
    default: return "default";
}

Answer 6

I've created a Nuget package (FluentSwitch) that should do what you want. So you can do the following:

var result = myValue.Switch()
    .When(1, "lalala")
    .When(2, "blalbla")
    .When(3, "lolollo")
    .Else("default")
    .Value();