How to resize 2d array?

[Revazi Tchitanava]

Hello. I'm trying to resize 2d array.

double array[1][1];
ArrayResize(array, 100, 100);
Print(array[50][10]);

Could anybody help me?

I'm trying it in MQL4

[Marco vd Heijden]

https://docs.mql4.com/array/arrayresize

The function can only be applied to dynamic array's.

[Revazi Tchitanava]

Marco vd Heijden:

https://docs.mql4.com/array/arrayresize

The function can only be applied to dynamic array's.

https://docs.mql4.com/basis/types/dynamic_array

Here is written: "Maximum 4-dimension array can be declared." and also example: 

double matrix[][10][20]; // 3-dimensional dynamic array
ArrayResize(matrix,5);   // Set the size of the first dimension

so i need to change not 1st dimension's size but 2nd's.

[Marco vd Heijden]

Well your first example

double array[1][1];
ArrayResize(array,

Shows a static array so not a dynamic.

[Snelle Moda]

Revazi Tchitanava:

https://docs.mql4.com/basis/types/dynamic_array

Here is written: "Maximum 4-dimension array can be declared." and also example: 

so i need to change not 1st dimension's size but 2nd's.

You can't resize the 2nd dimension of a multi dimensional array.

Only the first dimension can be changed.

Its a better to convert your 2-dimension array (maxtrix)

into a linear 1 dimensional array.

--------------------------------------------------------------

1e dimension = y | array index nr. for number of rows, start with 0

2e dimension = x | array index nr. for number of columns, start with 0

max width = max number of elements in the second dimension (x) your example ArrayResize(array, 100, 100) = max 100 elements

index number formula = (y * WIDTH) + x

You can now use the ArrayResize() function to change the size of the array

In your example ArrayResize(matrix, 100 * 100);

Greetings

[Revazi Tchitanava]

Snelle Moda:

You can't resize the 2nd dimension of a multi dimensional array.

Only the first dimension can be changed.

Its a better to convert your 2-dimension array (maxtrix)

into a linear 1 dimensional array.

--------------------------------------------------------------

1e dimension = y | array index nr. for number of rows, start with 0

2e dimension = x | array index nr. for number of columns, start with 0

max width = max number of elements in the second dimension (x) your example ArrayResize(array, 100, 100) = max 100 elements

index number formula = (y * WIDTH) + x

You can now use the ArrayResize() function to change the size of the array

In your example ArrayResize(matrix, 100 * 100);

Greetings

could you gave code example? compilable one. please. thank you.

[Snelle Moda]

Revazi Tchitanava:

could you gave code example? compilable one. please. thank you.

this example copies 10 CLOSE prices of a 1 minute and 1 day BARS to a data array and prints the values on the screen.

   int numberOfBars       = 10; // y axis | rows    | history BARS
   int numberOfPeriods    = 2;  // x axis | columns | PERIOD_M1 and PERIOD_D1

   ENUM_TIMEFRAMES period1_M1 = PERIOD_M1; // minute Bars
   ENUM_TIMEFRAMES period2_D1 = PERIOD_D1; // day bars
   
   double total_Data_Array[]; // array for both data sets
   ArrayResize(total_Data_Array, numberOfBars * numberOfPeriods);

   double a1[]; // temp array for data set 1
   CopyClose(Symbol(), period1_M1, 1, numberOfBars, a1); 
           
   double a2[]; // temp array for data set 2
   CopyClose(Symbol(), period2_D1, 1, numberOfBars, a2);

   for(int y = 0; y < numberOfBars; y++)
         {
// combine both array's
         int index1 = (y * numberOfPeriods) + 0; // data m1 period
         total_Data_Array[index1] = a1[y];
       
         int index2 = (y * numberOfPeriods) + 1; // data D1 period
         total_Data_Array[index2] = a2[y];                                 
         }

   for(int y = 0; y < numberOfBars; y++)
         {
         for(int x = 0; x < numberOfPeriods; x++)
               {
               int arrayIndexNr = (y * numberOfPeriods) + x;
               Alert("Close price for period: ", (x + 1), " = ", total_Data_Array[arrayIndexNr]);
               }       
         }