Question

I’ve used lambda expressions in other languages before using them in C#, and so I got in the habit of using _ for simple lambdas in the form of Func<T, TResult>, especially for simple lambdas where the body is just an expression representing the return value (predicates, etc..). However, in C# I often see single letters being used instead of _ for these same sorts of lambda expressions, such as x,y,z,i,j,k. The letter approach seems odd to me since those letters already have another typical meaning in common usage, for loop variables. _ is often easier to read in my opinion. Is the single letter style really the established style for lambdas in C#?

Examples:

what I’m used to writing:

var ages = people.Select(_ => _.Age);

What I’m seeing being written instead:

var ages = people.Select(x => x.Age); // choice of 'x' is not consistent

Answer 1

Many C# developers use _ to indicate that the parameter isn’t going to be used and a letter or other short name when the parameter is being used.

Other resources:

• Interesting discussion on using _ instead of ()