C#•3y ago

✅ Help in 2d matrix

var lines = Enumerable.Repeat(1, 4).ToArray();
var columns = Enumerable.Repeat(lines, 4).ToList();
columns[0][0] = 2;
Console.WriteLine(System.Text.Json.JsonSerializer.Serialize(columns));

//[[2,1,1,1],[2,1,1,1],[2,1,1,1],[2,1,1,1]]

var lines = Enumerable.Repeat(1, 4).ToArray();
var columns = Enumerable.Repeat(lines, 4).ToList();
columns[0][0] = 2;
Console.WriteLine(System.Text.Json.JsonSerializer.Serialize(columns));

//[[2,1,1,1],[2,1,1,1],[2,1,1,1],[2,1,1,1]]

Why does it changes all the inner arrays instead of the first one kekw

25 Replies

Angius•3y ago

Array is a reference type

Scarlet TetoOP•3y ago

ahbn

Angius•3y ago

You're filling the columns with 4 references to the same lines array

Scarlet TetoOP•3y ago

hey how to enumerable repeat by catbruh

Dellibrov•3y ago

What do you want to do ?

Angius•3y ago

I guess you could try a LINQ trick... maybe

Scarlet TetoOP•3y ago

im in caffeine overload, little bugged brain

Angius•3y ago

Enumerable.Repeat(0, 4).Select(_ => lines.ToArray()).ToList();

Enumerable.Repeat(0, 4).Select(_ => lines.ToArray()).ToList();

Scarlet TetoOP•3y ago

but Hmmmm thanks

Angius•3y ago

arr.ToArray() should create a copy

Scarlet TetoOP•3y ago

jusst toarray didnt work ill try this select one oh your solution did work! thanks whats your gh @? ill lik you as co author

MODiX•3y ago

Angius#1586

REPL Result: Success

var a1 = new int[]{1, 2, 3};
var a2 = Enumerable
    .Repeat(0, 4)
    .Select(_ => a1.ToArray())
    .ToList();

a2[1] = new int[]{4, 5, 6};

a2

var a1 = new int[]{1, 2, 3};
var a2 = Enumerable
    .Repeat(0, 4)
    .Select(_ => a1.ToArray())
    .ToList();

a2[1] = new int[]{4, 5, 6};

a2

Result: List<int[]>

Compile: 571.554ms | Execution: 83.665ms | React with ❌ to remove this embed.

MODiX•3y ago

Samarichitane#3472

REPL Result: Success

var board = Enumerable.Repeat('x', 64).Chunk(8);

board

var board = Enumerable.Repeat('x', 64).Chunk(8);

board

Result: <ChunkIterator>d__69<char>

[
  [
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x"
  ],
  [
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x"
  ],
  [
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x"
  ],
  [
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x"
  ],
  [
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x"
  ],
  [
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x"
  ],
  [
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x"
  ],
  [
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x"
  ]
]

[
  [
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x"
  ],
  [
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x"
  ],
  [
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x"
  ],
  [
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x"
  ],
  [
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x"
  ],
  [
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x"
  ],
  [
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x"
  ],
  [
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x",
    "x"
  ]
]