CODEWITHSUNDEEP
c#linqlist
Vincent
Vincent

Reputation: 1557

Counting value of all properties in generic list

I simply want to add up values from a specific list of custom objects I am currently doing it like this:

private int CountChances()
{
    int totalChance = 0;
    foreach(var chance in this.Chances)
    {
       totalChance += chance.Value;
    }
    return totalChance;
}

Is there a way to do this faster without the foreach loop? I'm almost certain linq should be able to do this quickly but I cannot seem to find how to do it.

Upvotes: 0

Views: 105

Answers (2)

SWeko
SWeko

Reputation: 30902

You can always do:

var sum = this.Chances.Sum(c => c.Value);

This is shorter and clearer coder. However, performance wise, the foreach might be just as fast or even faster.

Note, however, that the implementation of Sum uses checked mode, which can also affect the performance, so if your code is that critical, the foreach will be definitely faster.

However, we are talking about very fast code either way, if Chance is something like

class Chance {
    public long Value {get; set;}
}

and we have a list of 10 million items

var chances = Enumerable.Range(0, 10000000).Select(i => new Chance{Value = i});

on my machine, I'm getting 780ms for the foreach, and 1030ms for the Sum. So if your code goes nowhere near the million range, you're set with the Sum, as the code is way more obvious.

I.e. since your method is named CountChances, there's a chance that a support developer might mistake it's functioning, as it is not obvious at a glance that it actually sums the chances. No such chance with the Sum method.

Upvotes: 7

Aleksa
Aleksa

Reputation: 3114

You can do that like this:

this.Chances.Sum(e => e.Value);

Just include:

using System.Linq;

Upvotes: 5

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