c# - For vs. Linq - Performance vs. Future

Question

Very brief question. I have a randomly sorted large string array (100K+ entries) where I want to find the first occurance of a desired string. I have two solutions.

From having read what I can my guess is that the 'for loop' is going to currently give slightly better performance (but this margin could always change), but I also find the linq version much more readable. On balance which method is generally considered current best coding practice and why?

string matchString = "dsf897sdf78";
int matchIndex = -1;
for(int i=0; i<array.length; i++)
{
    if(array[i]==matchString)
    {
        matchIndex = i;
        break;
    }
}

or

int matchIndex = array.Select((r, i) => new { value = r, index = i })
                         .Where(t => t.value == matchString)
                         .Select(s => s.index).First();

question from:https://stackoverflow.com/questions/14893924/for-vs-linq-performance-vs-future

Answer 1

The best practice depends on what you need:

1. Development speed and maintainability: LINQ
2. Performance (according to profiling tools): manual code

LINQ really does slow things down with all the indirection. Don't worry about it as 99% of your code does not impact end user performance.

I started with C++ and really learnt how to optimize a piece of code. LINQ is not suited to get the most out of your CPU. So if you measure a LINQ query to be a problem just ditch it. But only then.

For your code sample I'd estimate a 3x slowdown. The allocations (and subsequent GC!) and indirections through the lambdas really hurt.