How to use LINQ on a multidimensional array to 'unwind' the array?

Question

Consider the following array:

int[,] numbers = new int[3, 2] { { 2, 1 }, { 3, 4 }, { 6, 5 } };

I would like to use LINQ to construct an IEnumerable with numbers 2, 1, 3, 4, 6, 5.

What would be the best way to do so?

There is a linq query in the duplicate, but i would go with a foreach as the linq query is quite opaque and the foreach is clear what you are doing. — Coding Flow
– Coding Flow, Commented Dec 11, 2012 at 15:21
'var flatNumbers = numbers.Cast<int>();' copied and modified from the linked post. All LINQ — Coding Flow
– Coding Flow, Commented Dec 11, 2012 at 15:24

Tim Schmelter · Accepted Answer · 2012-12-11 15:22:02Z

28

Perhaps simply:

var all = numbers.Cast<int>();

Demo

answered Dec 11, 2012 at 15:22

Tim Schmelter

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2 Comments

Sergey Berezovskiy Over a year ago

+1 from me - Cast is a has a little less overhead then OfType in this case

Jeppe Stig Nielsen Over a year ago

Upvoted. But in either way we get boxing and unboxing because this goes through the non-generic IEnumerable interface which yields object boxes which are the unboxed by Cast.

mihai · Accepted Answer · 2014-12-07 19:11:04Z

7

How about:

Enumerable
    .Range(0,numbers.GetUpperBound(0)+1)
    .SelectMany(x => Enumerable.Range(0,numbers.GetUpperBound(1)+1)
    .Select (y =>numbers[x,y] ));

or to neaten up.

var xLimit=Enumerable.Range(0,numbers.GetUpperBound(0)+1);
var yLimit=Enumerable.Range(0,numbers.GetUpperBound(1)+1);
var result = xLimit.SelectMany(x=> yLimit.Select(y => numbers[x,y]));

EDIT Revised Question....

var result = array.SelectMany(x => x.C);

edited Dec 7, 2014 at 19:11

mihai

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answered Dec 11, 2012 at 15:29

Bob Vale

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Comments

Sergey Berezovskiy · Accepted Answer · 2012-12-11 15:38:03Z

6

Use simple foreach to get your numbers from 2d array:

int[,] numbers = new int[3, 2] { { 2, 1 }, { 3, 4 }, { 6, 5 } };
foreach(int x in numbers)
{
   // 2, 1, 3, 4, 6, 5.
}

LINQ (it's an big overhead to use Linq for your initial task, because instead of simple iterating array, CastIterator (Tim's answer) of OfTypeIterator will be created)

IEnumerable<int> query = numbers.OfType<int>();

edited Dec 11, 2012 at 15:38

answered Dec 11, 2012 at 15:18

Sergey Berezovskiy

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3 Comments

Kees C. Bakker Over a year ago

I need to use LINQ. My problem is a tat more complex... but I need to use LINQ. Each object in the array has a property that has an array that I'll need to mash into a single list.

Coding Flow Over a year ago

Please post your whole problem as you will get different answers

Arnoud van der Leer Over a year ago

It may be homework, but it may also be the smallest working example of a mind-bogglingly complex system, which the asker didn't want to bother us with ;-)

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