push a two-dimensional array

Question

I m trying to push to a two-dimensional array without it messing up  currently My array is   var myArray      1 1 1 1 1    1 1 1 1 1    1 1 1 1 1      And my code I m trying is   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  lt  rows  i          for  var j   c  j  lt  cols  j                  myArray i  j  push 0             That should result in the following   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   So the question is how would I accomplish this

User · Answer

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).

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.

 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);
  };

User · Answer

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  for  var i   0  i  lt  rows - 1  i        for  var j   c  j  lt  cols  j            myArray i  push 0           for  var i   r  i  lt  rows - 1  i         for  var j   0  j  lt  cols  j              col push 0           you can also combine the two loops using an if condition  if row  lt  r  else if row    r

User · Answer

Iterating over two dimensions means you ll need to check over two dimensions   assuming you re starting with   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   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   Start with the outer array   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   var i      rows      myArray  rows   8  myArray            see first example above for  i   0  i  lt  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   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  lt  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  lt  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

User · Answer

In your case you can do that without using push at all   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  lt  newRows  i          item   myArray i      myArray i              for  var k   item length  k  lt  newCols  k            item k    0

User · Answer

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   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  lt  rows  i        var start    if  i  lt  r        start    c      else       start   0      myArray push            for  var j   start  j  lt  cols  j              myArray i  push 0

User · Answer

Create am array and put inside the first  in this case i get data from JSON response    getJSON   Tool GetAllActiviesStatus       var dataFC   new Array       function  data          for  var i   0  i  lt  data Result length  i                var serie   new Array data Result i  FUNCAO  data Result i  QT  true  true             dataFC push serie

User · Answer

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  lt  rows  i         for  var j   0  j  lt  cols  j            if j  lt   c  amp  amp  i  lt   r          myArray i  j    1        else         myArray i  j    0

User · Answer

You have some errors in your code    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    One correct  although kind of verbose version  would be the following   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 lt rows  i         myArray push              expand all rows to have the correct amount of cols for  var i   0  i  lt  rows  i          for  var j    myArray i  length  j  lt  cols  j                  myArray i  push 0

[javascript] push() a two-dimensional array

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