Reasons to Learn LINQ

Question

I don't know LINQ, but from reading a lot around this site and others, it's a MUST HAVE skill for C# developers.

The problem is I am so booked on projects at work I have no time to pick up LINQ, I need to convince my boss to let me (and fellow coders) set aside some time so that we can become a LINQ house.

So.. my question is, what are the productivity gains? (percentages or some kind of solid numbers, maybe even estimates) What are the security, maintenance, etc, advantages?

I'm looking for something a little more solid than anecdotal evidence, he's not a tech guy, so I have to speak it in numbers, numbers that translate to dollars and cents.

Answer 1

Tell him that everywhere you loop through objects and data you can use Linq and this will increase your productivity and quality.

After that you can search your code and tell how many times you could use it.

Answer 2

Well I'm perhaps the wrong guy to answer this but then again I'm opiniated so what the hey.

I don't really believe in training courses. They're expensive and hte idea that you can turn someone into a C# or Java developer in a week is, well, patently ridiculous, a waste of $4000 and a loss of a week of developer time.

No time at work? Let me put this in perspective for you. Imagine you were at an interview. I, as the interviewer ask you this question:

Q: Have you learnt any LINQ?

And you gave this answer:

A: I'm on so many projects at work I have had no time to learn.

Do you know what I would do? I would politely thank you for coming in, tell you we'd let you know and then toss your CV in the bin as soon as you were out the door.

Why? Because developers--good developers at any rate--take their own time to learn new stuff. It's an ever-changing industry and the rate of change is substantial. Good developers learn something not because there's some commercial advantage in it or not because it fills some perceived CV gap and definitely not because they've seen a lot of jobs advertised that mention it.

Good developers learn new things because they're interested in them.

If you're relying on work to give you the time and motivation to learn something then sorry, you are just lacking in motivation.

Answer 3

Linq can lead to drastic reductions in line count, when manipulating data.

E.g. use

using System.Linq;
var index = collection
    .Where(i => i.SomeCondition())
    .ToLookup(i => i.Key);

instead of the much more verbose

var index = new Dictionary<Key, List<Value>>();
foreach(var i in collection)
{
    if (i.SomeCondition())
    {
        if (!index.ContainsKey(i.Key))
        {
            index[i.Key] = new List<Value>();
        }
        index[i.Key].Add(i);
    }
}

That's a factor of two in LOCs, even on such a trivial example.

Even if you do not get any time for formal training, you can try to spend a minute every time you have to loop over a collection to look into some Linq reference. It may pay off in reduced typing and improved legibility faster than you'd expect.

Answer 4

LINQ is a language construct that can query just about any iterable object, not just databases. This includes lists, dictionaries, xml, sql, etc.

Its this unification that makes it powerful. You no longer need to write annoying helper functions to do simple things like "find every string in this list that starts with the letter A", instead it becomes a single LINQ statement. Likewise, the exact same statement can be used to query a similar SQL structure by simply pointing it at a different data source.

Not only does this make things easier, it makes things significantly more consistent. Each of those helper functions could potentially be poorly coded by a peer, or contain bugs, or need to be organized into some messy "helper library"; all of this is moot with LINQ.

Also, Visual Studio 2008 has native support for LINQ queries, meaning you get intellisense for free. This is not the case with raw SQL statements in strings, or even SQL data adapters beyond the auto-discovery of the adapter's own properties.

So to sum it up: Unification and consistency.

Answer 5

If you can convince your boss to let you learn new programming languages and technologies on company time, more power to you; but I wouldn't expect to, if I were you. Learn it on your own and help your fellow coders do the same.

Answer 6

I believe that LINQ increases coder productivity, decreases line count, and decreases bugs. Writing loops can be difficult when the logic is convoluted. LINQ allows you to implement many relatively complex operations in a much smaller number of commands, with the benefit of MS doing all of your testing. Additionally, LINQ is much closer to how the human brain works. Everyone understands Orderby and Select intuitively, while the loops to implement these operations are not necessarily intuitive. Additionally, MS will continue to optimize the LINQ queries and at some point provide an automatic parallelization. While loops are difficult for the compiler to automatically parallelize, expression trees are not. Sometimes you will need to specify the parallelization (i.e. PLINQ), but eventually, many of the LINQ operators will probably be parallelized.

Answer 7

Edit: I read the question as "Help me sell linq to my boss" rather than "linq training". Linq is extremely useful and it's use should be encouraged, but I don't think that it requires training. It's all very well documented online, and the concepts should be familiar to anyone who's ever written a SQL query.

We just had one developer (me) do a bunch of reading and give a quick intro to other developers and went from there.

As for my original linq justification:

The biggest selling point for me is that linq lets you perform many list manipulations in a way that does a lot better job of expressing your intent than the non-linq way.

If you look at all of the places in your code where you're looping over a collection (whether with a for loop, or a foreach loop) chances are good you're doing one of (or a combination of) three things:

• mapping (transforming each element into something else)
• filtering (finding all elements that match a certain criteria)
• aggregating (eg. calculating the sum of a collection of integers)

For example, filtering items out of a list is a reasonably common operation (at least for me). The non-linq way requires a foreach loop and an if at minimum:

foreach(Car c in cars)
{
    if (c.Color == "Red")
    {
        newList.Add(c);
    }
 }

There's a lot of accidental complexity there for what should be a simple operation. Compare the linq equivalent:

var filteredItems = from car in cars
                        where car.Color == "Red"
                        select car;

In my mind, that's a lot more readable, and exactly expresses it's intent.

Answer 8

A more appropriate approach would be "Help me sell LINQ to my boss".

Answer 9

You coulda spent the time you spent reading these answers and posting the question learning a lil bit of LINQ. If it is "MUST HAVE" then grok it yourself as it is part of your own development.

From the business viewpoint it is just syntactic sugar that doesn't add any direct business benefit as learning another tech might, so to be brutually honest I think you're going to have to rely on some fuzzy logic to justify it, which is going to be hard to prove.

Answer 10

You don't. Instead of going on a course, you spend 15-30 minutes reading about the basics, and then you start using LINQ. When you get stuck, you spend another 10 minutes reading, and then you use it some more.