What is the difference between Contains and Any in LINQ?

Question

What is the difference between Contains and Any in LINQ?

Answer 1

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

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

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