Javascript push() 一个二维数组
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push() a two-dimensional array
提问by Jo3la
I'm trying to push to a two-dimensional array without it messing up, currently My array is:
我正在尝试推送到一个二维数组而不会弄乱它，目前我的数组是：
var myArray = [
[1,1,1,1,1],
[1,1,1,1,1],
[1,1,1,1,1]
]
And my code I'm trying is:
我正在尝试的代码是：
var r = 3; //start from rows 3
var c = 5; //start from col 5
var rows = 8;
var cols = 7;
for (var i = r; i < rows; i++)
{
for (var j = c; j < cols; j++)
{
myArray[i][j].push(0);
}
}
That should result in the following:
这应该导致以下结果：
var myArray = [
[1,1,1,1,1,0,0],
[1,1,1,1,1,0,0],
[1,1,1,1,1,0,0],
[0,0,0,0,0,0,0],
[0,0,0,0,0,0,0],
[0,0,0,0,0,0,0],
]
But it doesn't and not sure whether this is the correct way to do it or not.
但它并不确定这是否是正确的方法。
So the question is how would I accomplish this?
所以问题是我将如何实现这一点？
回答by Sirko
You have some errors in your code:
您的代码中有一些错误：
- Use
myArray[i].push( 0 );to add a new column. Your code (myArray[i][j].push(0);) would work in a 3-dimensional array as it tries to add another element to an array at position[i][j]. - You only expand (col-d)-many columns in all rows, even in those, which haven't been initialized yet and thus have no entries so far.
- 使用
myArray[i].push( 0 );添加一个新列。您的代码 (myArray[i][j].push(0);) 将在 3 维数组中工作，因为它会尝试将另一个元素添加到位置 的数组中[i][j]。 - 您只在所有行中扩展 (col-d)-许多列，即使在那些尚未初始化的列中，因此到目前为止还没有条目。
One correct, although kind of verbose version, would be the following:
一个正确的，虽然有点冗长的版本，如下：
var r = 3; //start from rows 3
var rows = 8;
var cols = 7;
// expand to have the correct amount or rows
for( var i=r; i<rows; i++ ) {
myArray.push( [] );
}
// expand all rows to have the correct amount of cols
for (var i = 0; i < rows; i++)
{
for (var j = myArray[i].length; j < cols; j++)
{
myArray[i].push(0);
}
}
回答by Guffa
You have to loop through all rows, and add the missing rows and columns. For the already existing rows, you loop from c to cols, for the new rows, first push an empty array to outer array, then loop from 0 to cols:
您必须遍历所有行，并添加缺少的行和列。对于已经存在的行，从 c 循环到 cols，对于新行，首先将一个空数组推送到外部数组，然后从 0 循环到 cols：
var r = 3; //start from rows 3
var c = 5; //start from col 5
var rows = 8;
var cols = 7;
for (var i = 0; i < rows; i++) {
var start;
if (i < r) {
start = c;
} else {
start = 0;
myArray.push([]);
}
for (var j = start; j < cols; j++) {
myArray[i].push(0);
}
}
回答by zzzzBov
Iterating over two dimensions means you'll need to check over two dimensions.
迭代两个维度意味着您需要检查两个维度。
assuming you're starting with:
假设你从：
var myArray = [
[1,1,1,1,1],
[1,1,1,1,1],
[1,1,1,1,1]
]; //don't forget your semi-colons
You want to expand this two-dimensional array to become:
你想把这个二维数组展开成：
var myArray = [
[1,1,1,1,1,0,0],
[1,1,1,1,1,0,0],
[1,1,1,1,1,0,0],
[0,0,0,0,0,0,0],
[0,0,0,0,0,0,0],
[0,0,0,0,0,0,0],
];
Which means you need to understand what the difference is.
这意味着您需要了解区别是什么。
Start with the outer array:
从外部数组开始：
var myArray = [
[...],
[...],
[...]
];
If you want to make this array longer, you need to check that it's the correct length, and add more inner arrays to make up the difference:
如果你想让这个数组更长，你需要检查它的长度是否正确，并添加更多的内部数组来弥补差异：
var i,
rows,
myArray;
rows = 8;
myArray = [...]; //see first example above
for (i = 0; i < rows; i += 1) {
//check if the index exists in the outer array
if (!(i in myArray)) {
//if it doesn't exist, we need another array to fill
myArray.push([]);
}
}
The next step requires iterating over every column in every array, we'll build on the original code:
下一步需要迭代每个数组中的每一列，我们将在原始代码的基础上构建：
var i,
j,
row,
rows,
cols,
myArray;
rows = 8;
cols = 7; //adding columns in this time
myArray = [...]; //see first example above
for (i = 0; i < rows; i += 1) {
//check if the index exists in the outer array (row)
if (!(i in myArray)) {
//if it doesn't exist, we need another array to fill
myArray[i] = [];
}
row = myArray[i];
for (j = 0; j < cols; j += 1) {
//check if the index exists in the inner array (column)
if (!(i in row)) {
//if it doesn't exist, we need to fill it with `0`
row[j] = 0;
}
}
}
回答by ZER0
In your case you can do that without using pushat all:
在您的情况下，您可以完全不使用push：
var myArray = [
[1,1,1,1,1],
[1,1,1,1,1],
[1,1,1,1,1]
]
var newRows = 8;
var newCols = 7;
var item;
for (var i = 0; i < newRows; i++) {
item = myArray[i] || (myArray[i] = []);
for (var k = item.length; k < newCols; k++)
item[k] = 0;
}
回答by Daniel
var r = 3; //start from rows 3
var c = 5; //start from col 5
var rows = 8;
var cols = 7;
for (var i = 0; i < rows; i++)
{
for (var j = 0; j < cols; j++)
{
if(j <= c && i <= r) {
myArray[i][j] = 1;
} else {
myArray[i][j] = 0;
}
}
}
回答by Moataz Elmasry
you are calling the push() on an array element (int), where push() should be called on the array, also handling/filling the array this way makes no sense you can do it like this
您正在数组元素 (int) 上调用 push()，其中应该在数组上调用 push()，也以这种方式处理/填充数组没有意义，您可以这样做
for (var i = 0; i < rows - 1; i++)
{
for (var j = c; j < cols; j++)
{
myArray[i].push(0);
}
}
for (var i = r; i < rows - 1; i++)
{
for (var j = 0; j < cols; j++)
{
col.push(0);
}
}
you can also combine the two loops using an if condition, if row < r, else if row >= r
您还可以使用 if 条件组合两个循环，if row < r, else if row >= r
回答by CelzioBR
Create am array and put inside the first, in this case i get data from JSON response
创建 am 数组并放入第一个数组中，在这种情况下，我从 JSON 响应中获取数据
$.getJSON('/Tool/GetAllActiviesStatus/',
var dataFC = new Array();
function (data) {
for (var i = 0; i < data.Result.length; i++) {
var serie = new Array(data.Result[i].FUNCAO, data.Result[i].QT, true, true);
dataFC.push(serie);
});
回答by RWasson
The solution below uses a double loop to add data to the bottom of a 2x2 array in the Case 3. The inner loop pushes selected elements' values into a new row array. The outerloop then pushes the new row array to the bottom of an existing array (see Newbie: Add values to two-dimensional array with for loops, Google Apps Script).
下面的解决方案使用双循环将数据添加到案例 3 中的 2x2 数组的底部。内部循环将选定元素的值推送到新的行数组中。然后，外循环将新的行数组推送到现有数组的底部（请参阅新手：使用 for 循环将值添加到二维数组，Google Apps 脚本）。
In this example, I created a function that extracts a section from an existing array. The extracted section can be a row (full or partial), a column (full or partial), or a 2x2 section of the existing array. A new blank array (newArr) is filled by pushing the relevant section from the existing array (arr) into the new array.
在这个例子中，我创建了一个从现有数组中提取一个部分的函数。提取的部分可以是现有数组的一行（全部或部分）、一列（全部或部分）或 2x2 部分。通过将现有数组 (arr) 中的相关部分推送到新数组中来填充新的空白数组 (newArr)。
function arraySection(arr, r1, c1, rLength, cLength) {
rowMax = arr.length;
if(isNaN(rowMax)){rowMax = 1};
colMax = arr[0].length;
if(isNaN(colMax)){colMax = 1};
var r2 = r1 + rLength - 1;
var c2 = c1 + cLength - 1;
if ((r1< 0 || r1 > r2 || r1 > rowMax || (r1 | 0) != r1) || (r2 < 0 ||
r2 > rowMax || (r2 | 0) != r2)|| (c1< 0 || c1 > c2 || c1 > colMax ||
(c1 | 0) != c1) ||(c2 < 0 || c2 > colMax || (c2 | 0) != c2)){
throw new Error(
'arraySection: invalid input')
return;
};
var newArr = [];
// Case 1: extracted section is a column array,
// all elements are in the same column
if (c1 == c2){
for (var i = r1; i <= r2; i++){
// Logger.log("arr[i][c1] for i = " + i);
// Logger.log(arr[i][c1]);
newArr.push([arr[i][c1]]);
};
};
// Case 2: extracted section is a row array,
// all elements are in the same row
if (r1 == r2 && c1 != c2){
for (var j = c1; j <= c2; j++){
newArr.push(arr[r1][j]);
};
};
// Case 3: extracted section is a 2x2 section
if (r1 != r2 && c1 != c2){
for (var i = r1; i <= r2; i++) {
rowi = [];
for (var j = c1; j <= c2; j++) {
rowi.push(arr[i][j]);
}
newArr.push(rowi)
};
};
return(newArr);
};
