CODEWITHSUNDEEP
javascriptarraysfunctionmultidimensional-arrayarrow-functions
KeoneShyGuy
KeoneShyGuy

Reputation: 1

How do you pass a 2d array as a param in javascript?

I'm trying to access a specific element in an array, but I'm only getting the first one. Any help with pointing out my error is appreciated.

let testArr = [[1, 2, 3],[4, 5, 6]];
const printArr = (someArr, i) => alert(someArr[i]);
printArr(testArr, [0][0]);

Expected Output

1

Actual Output

1, 2, 3

Upvotes: 0

Views: 390

Answers (4)

Vlad B.
Vlad B.

Reputation: 2937

Or you could just do it without casting array like numbers or similar.

let testArr = [
    [1, 2, 3],
    [4, 5, 6],
];
const printArr = (someArr, arrNum, indNum) => someArr[arrNum][indNum];

printArr(testArr, 1, 0);

Upvotes: 0

junvar
junvar

Reputation: 11584

[0][0] is actually 0. This is the same as

a = [0];
a[0] === [0][0]; // 0

What you want to actually do is unclear. If you just want to pass a value, just pass that value, rather than the array and index separately.

printArr(testArr[0][0]);

If, for whatever reason, you need the index and array passed separately, then you can pass the indies as an array:

let testArr = [
  [1, 2, 3],
  [4, 5, 6],
  [7, [8, 9], 10]
];
const printArr = (arr, indices) => console.log(indices.reduce((a, i) => a[i], arr));
printArr(testArr, [2, 1, 0]); // 8

Upvotes: 3

Nina Scholz
Nina Scholz

Reputation: 386680

You could take a function for getting a special value.

let testArr = [[1, 2, 3],[4, 5, 6]];

const printArr = (someArr, fn) => console.log(fn(someArr));

printArr(testArr, array => array[0][0]);

Upvotes: 0

Quentin
Quentin

Reputation: 943996

printArr(testArr, [0][0]);

aproximates to:

const some_array = [0];
const second_arg = some_array[0]
printArr(testArr, second_arg);

You are passing 0 as the second argument.

You can't pass arbitrary bits of JS syntax around.

Use two arguments instead.

let testArr = [[1, 2, 3],[4, 5, 6]];
const printArr = (someArr, i, j) => alert(someArr[i][j]);
printArr(testArr, 0, 0);

Upvotes: 1

Related Questions