I have List<Product[]> and I need to join them into one Product[].
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Please put a little more work into making your questions clearer in the future.Dave Markle– Dave Markle2009-07-24 11:42:53 +00:00Commented Jul 24, 2009 at 11:42
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14Next time be more helpfull DaveIgor Golodnitsky– Igor Golodnitsky2009-07-24 12:58:43 +00:00Commented Jul 24, 2009 at 12:58
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4Nothing wrong with the question.snowcode– snowcode2017-03-03 11:48:47 +00:00Commented Mar 3, 2017 at 11:48
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3 Answers
You can use SelectMany and then ToArray to do this.
var result = source.SelectMany(i => i).ToArray();
answered Jul 24, 2009 at 11:33
Daniel Earwicker
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Comments
You can use .Concat() extension method as well, and then .ToArray():
x.Concat(y).Concat(z).ToArray();
Comments
For any more complex joins IEnumerable, GetEnumerator and yield are your friends and are super performant. Just for fun, here's some code showing extending Linq with your own custom methods does not have to be scary;
public static class MyLinqExtensions
{
public static IEnumerable<int> RoundRobin(this IEnumerable<int> a, IEnumerable<int> b)
{
var ae = a.GetEnumerator();
var be = b.GetEnumerator();
bool aHasNumber = ae.MoveNext();
bool bHasNumber = be.MoveNext();
while (aHasNumber || bHasNumber)
{
if (aHasNumber)
{
yield return ae.Current;
aHasNumber = ae.MoveNext();
}
if (bHasNumber)
{
yield return be.Current;
bHasNumber = be.MoveNext();
}
}
}
}
void Main()
{
var arr1 = new[] { 1, 2, 3, 4 };
var arr2 = new[] { 4, 5, 6 };
var arr3 = new[] { 7, 8, 9};
var arr4 = new int[] { };
// arrays the same size
Assert.AreEqual(new[] { 4, 7, 5, 8, 6, 9 }, arr2.RoundRobin(arr3).ToArray());
// array 1 bigger than array 2
Assert.AreEqual(new[] { 1, 4, 2, 5, 3, 6, 4 }, arr1.RoundRobin(arr2).ToArray());
// array 1 smaller than 2
Assert.AreEqual(new[] { 4, 1, 5, 2, 6, 3, 4 }, arr2.RoundRobin(arr1).ToArray());
// 2 empty, 1 not
Assert.AreEqual(new[] { 4, 5, 6 }, arr2.RoundRobin(new int[] { }).ToArray());
// 1 empty, 2 not
Assert.AreEqual(new[] { 1, 2, 3, 4 }, arr1.RoundRobin(new int[] { }).ToArray());
// both empty
Assert.AreEqual(new int[] { }, arr4.RoundRobin(arr4).ToArray());
// prove it's Linq
Assert.AreEqual(new[] { 1, 4, 2}, arr1.RoundRobin(arr2).Take(3).ToArray());
Console.WriteLine("pass");
}
