What is the difference between Contains and Any in LINQ?

Question

What is the difference between Contains and Any in LINQ?

Not sure why I would get downvoted, perfectly valid question — user2202911, May 07 '14 at 19:37
I think it's been answered here: http://stackoverflow.com/questions/4445219/linq-ring-any-vs-contains-for-huge-collections — msmolcic, May 07 '14 at 19:38
@msmolcic92 That's a question regarding performance...this is not. — user2202911, May 07 '14 at 19:39
Documentation is at http://msdn.microsoft.com/en-us/library/system.linq.enumerable.aspx — Tim S., May 07 '14 at 19:39
@Joce Stop it with the strawman. I couldn't find anything on Contains & Any, everything I came across on google was regarding LINQ introductions and tutorials. — user2202911, May 07 '14 at 19:45
It's all explained right in MS's own documentation. [Any](http://msdn.microsoft.com/en-us/library/bb337697.aspx) vs. [Contains](http://msdn.microsoft.com/en-us/library/bb352880.aspx). — joce, May 07 '14 at 19:48
@Joce Here's the thing.. I could not find that page. Hence the question — user2202911, May 08 '14 at 00:08

score 65 · Accepted Answer · edited Jun 30 '15 at 18:39

65

Contains takes an object, Any takes a predicate.

You use Contains like this:

listOFInts.Contains(1);

and Any like this:

listOfInts.Any(i => i == 1);
listOfInts.Any(i => i % 2 == 0); // Check if any element is an Even Number

So if you want to check for a specific condition, use Any. If you want to check for the existence of an element, use Contains.

MSDN for Contains, Any

edited Jun 30 '15 at 18:39

dub stylee

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answered May 07 '14 at 19:36

BradleyDotNET

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Technically, Contains takes a TSource, which is either a `Struct` or `Object` depending on how the Collection was defined... – JJS Apr 15 '19 at 15:39
1

@JJS I meant "object" in the general "everything in C# is an object" sense. Ie, could be an `int`, a `string`, some struct, or a `MyClass`. You are correct of course though – BradleyDotNET Apr 15 '19 at 16:11

score 16 · Answer 2 · answered May 07 '14 at 19:38

Contains checks if the sequence contains a specified element.

Enumerable.Any checks if element of a sequence satisfies a condition.

Consider the following example:

List<int> list = new List<int> { 1, 2, 3, 4, 5 };
bool contains = list.Contains(1); //true

bool condition = list.Any(r => r > 2 && r < 5);

JJS · Answer 3 · 2019-04-15T15:38:22.850

Contains cares about whether the source collection is an ICollection, Any does not.

Enumerable.Contains http://referencesource.microsoft.com/#System.Core/System/Linq/Enumerable.cs#f60bab4c5e27a849

public static bool Contains<TSource>(this IEnumerable<TSource> source, TSource value)
{
    ICollection<TSource> collection = source as ICollection<TSource>;
    if (collection != null)
    {
        return collection.Contains(value);
    }
    return source.Contains<TSource>(value, null);
}

Enumerable.Any http://referencesource.microsoft.com/#System.Core/System/Linq/Enumerable.cs#6a1af7c3d17845e3

public static bool Any<TSource>(this IEnumerable<TSource> source, Func<TSource, bool> predicate)
{
    foreach (TSource local in source)
    {
        if (predicate(local))
        {
            return true;
        }
    }
    return false;
}

That's not the *only* difference, but it is one I didn't know about! — BradleyDotNET, May 07 '14 at 19:51

score 2 · Answer 4 · answered Sep 14 '19 at 06:59

2

Another difference as mentioned here is on the performance

Contains is O(n) for a List and O(1) for a HashSet
Any is simply O(n)

answered Sep 14 '19 at 06:59

Hossein Narimani Rad

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1

True, but this question is about the extension method `Enumerable.Contains`, not the interface method `ICollection.Contains`. – Theodor Zoulias Sep 14 '19 at 07:15

score 0 · Answer 5 · answered May 07 '14 at 19:40

0

Contains

Determines whether a sequence contains a specified element by using the default equality comparer.

Any

Determines whether a sequence contains any elements.

As for the documentation:

Can't seem to find to find any documentation on it.

All (most?) LINQ extension methods: here

answered May 07 '14 at 19:40

RobIII

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That is one overload of Any (and the one that is less commonly used). I would at least include the more commonly used overload in your answer. – BradleyDotNET May 07 '14 at 19:41
My answer already includes **all** overloads ;) (and all (most?) other LINQ extension methods) – RobIII May 07 '14 at 19:41

What is the difference between Contains and Any in LINQ?

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