The Devlineator

Been away for a while working on a 107,000 hour project. It isn?t done, but I am making time to blog and do my technical mentorship, because I have come to realize that there will always be high priority projects. You have to take the time to train and mentor during those projects because of that. Now on to the show.

I know that LINQ has received a massive welcome from the community and I have to say that it is a deserved on. On the whole it is a great addition to the language. I however don?t like one part of it. Verbose LINQ. I realize that it is more SQL like and that it is perceived to  shorten the learning curve, but I disagree. Lambdas are where the true power of LINQ sit and using verbose to me seems to focus you to learn LINQ one way so that you can re-learn it another.

I am going to focus on the Lambda side of LINQ simply out of preference. Keep an eye out here for the verbose VS. lambda death match, but that is a post for another time.

Lambda statements are actually fairly simple once you break them up.

SomeList.Where(c=>c.Id == someInt);

The above is the lambda conversion of this code block

foreach (Item item in SomeList)
{
    If(item.Id == soemInt)
        SomeOtherList.Add(item);
}

Lets break down the lambda so that this is a bit more clear.

c =>

This statement is declaring that the item in the list we are looking at is going to be held in the local variable named ?c?. This is no different than naming the variable in a for each loop ?c?. You can name your lambda variables more intuitively and I would encourage you to do so. Something like this.

SomeList.Where(menuItem => MenuItem.Id == someInt);

Once the object is declared you have the ability to use all of the members of that object. That is how we are able to use the ?Id? property to check something for a Boolean property. Selecting based on some Boolean expression is the most common use for Lambdas but not the only one.

List<SubMenu> submenus = SomeList.Select(menuItem => new SubMenu() 
                                                   {
                                                         ParentMenuId = menuItem.Id 
                                                   });

In this example we have created a submenu item from all the menu items in the list. We did this through the power of LINQ to let use change the output type of the selection at will. This is very usefull when you are creating items from other items. The code block that would represent is:

List<SubMenu> SubMenus = new List<SubMenu>();

foreach(MenuItem item in SomeList)
{
    SubMenu subMenu = new SubMenu();
    subMenu.ParentMenuId = item.Id;
    SomeOtherList.Add(subMenu);
}

To me this power is amazing. I have the ability to replace entire loops with a single line. The hit to readability is a concern but lambdas lend themselves to so many applications, and are key to LINQ so it should be part of the core toolset of a developer. If you use some sense and name your lambda variables intuitively you should get a lot of great millage out of LINQ without losing your readability.

C#, C# Helpful Functions, .NET