int[ ][ ] myArr = { {1, 2, 3}, {4}, {5, 6, 7} }; why are there only 2 [ ] in the array declaration?

Question

multi dimentional arrays

Answer 1

https://www.sololearn.com/learn/Java/2148/?ref=app
https://www.sololearn.com/learn/Java/2149/?ref=app
1d array ... set of values
2d array ... set of 1d array
3d array ... set of 2d array
//mine definitions 😂

Answer 2

No. Dimensions do not concern "how many arrays" you have. Dimensions are about how many levels your array is nested within.

In {{1, 2, 3}, {4}, {5, 6, 7}},

arr[0] would refer to {1, 2, 3}
arr[1] would refer to {4}
arr[2] would refer to {5, 6, 7}

arr[0][0] would refer to 1, which is the first element in the first array within the multidimensional array. Similarly :

arr[0][1] would refer to 2
arr[1][0] would refer to 4
arr[2][1] would refer to 6

You would need three dimensions when you have:

{{1, 2, {3, 4}}, {5}, {6, 7}}

Note that {3, 4} is within {1, 2, {3, 4}}, and is represented by arr[0][2]. To access 4, for example, would be arr[0][2][1].

Answer 3

Because specifying two dimensions would be enough to identify each element in the array, as it is.

Answer 4

so if you had 4 arrays you would need 3 sets of brackets etc ?

Answer 5

the simple answer is it is a 2 dimensional array
if explained further,
[] means 1 dimension
[] [] means 2 dimensions
when we need to reference an element in a 2 dimensional array we use 2 indexes
e.g :-
int x=myarr[0][1] //x=2
think of 2 dimensional array as a table

× 0 1 2 - X

0 1 4 5

1 2 6

2 3 7

-Y

X- array numbers (1st array gets 0, 2nd array gets 1.. and so on)

Y- index of each array