This article tells you when to get the first element of the array, which method to use higher performance.
We need to know that two methods are methods of Linq, Linq need to reference before use. For List, etc. are inherited enumerable Enumerablethen get the first element can be used FirstOrDefault. If you use the Findtype you need the array is IList.
The following write a simple example
Find decompile the code can be seen below, the following code to delete some code, so that we are more likely to see is for use Find and use judgment
private T[] _items;
public T Find(Predicate<T> match)
{
for (int index = 0; index < this._size; ++index)
{
if (match(this._items[index]))
return this._items[index];
}
return default (T);
}
The FirstOrDefault code exists foreach, which calls the GetEnumerator method of the list, but also at the end of the call to Dispose. Such performance would FirstOrDefault slightly worse than Find.
public static TSource FirstOrDefault<TSource>(this IEnumerable<TSource> source, Func<TSource, bool> predicate)
{
foreach (TSource source1 in source)
{
if (predicate(source1))
return source1;
}
return default (TSource);
}
So for the Listtype of first obtaining a default or use the Find, other useFirstOrDefault
-
For List, use for at twice the rate of foreach
-
Traversing the array is traversed twice the speed of List
-
Use for traversing the array using foreach to traverse speed is 5 times List
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