Copy 2D Array in C#

Question

I have a code that stored the data to a temporary array.

string filename = openFileDialog1.FileName;
string[] line = File.ReadAllLines(filename);
using (var reader2 = File.OpenText(@filename))
{
    for (int i = 0; i < line.Length; i++)
    {
        string lines = reader2.ReadLine();
        var data = lines.Split(',');
        double[,] arrayTemp = new double[line.Length, 2];
        arrayTemp[i, 0] = double.Parse(data[0]);
        arrayTemp[i, 1] = double.Parse(data[1]);
    }
    Array.Copy(arrayTemp, GlobalDataClass.dDataArray, line.Length); //error the name "arrayTemp" does not exist in the current context.
}

Since 2d array is not resizable and I want my global array to be flexible,so I use the Array.Copy method to copy the temp array to the Global class array. However I got an error as commented in my code above.

My question is how to copy the tempArray to the global class array. Any idea how to fix this?

Sudhakar Tillapudi · Accepted Answer · 2014-02-20 03:16:02Z

3

Problem : You have declared your array variable arrayTemp inside the for loop and it is not available outside of it.

Solution : You need to move your array variable arrayTemp declaration outside the loop.

Try This:

 string filename = openFileDialog1.FileName;
 string[] line = File.ReadAllLines(filename);
 double arrayTemp=new double[line.Length,2];//declare outside forloop so it available after forloop.
 GlobalDataClass.dDataArray=new double[line.Length,2]; //add this line
 using (var reader2 = File.OpenText(@filename))
 {
   for (int i = 0; i < line.Length; i++)
   {
     string lines = reader2.ReadLine();
     var data = lines.Split(',');         
     GlobalDataClass.dDataArray[i, 0] = double.Parse(data[0]);
     GlobalDataClass.dDataArray[i, 1] = double.Parse(data[1]);
   }
    Array.Copy(arrayTemp, GlobalDataClass.dDataArray, line.Length); 
 }

edited Feb 20, 2014 at 3:16

answered Feb 20, 2014 at 2:34

Sudhakar Tillapudi

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6 Comments

Sudhakar Tillapudi Over a year ago

@Cyral: Thanks for your Kind support :)

Ren Over a year ago

I follow your codes, but now I have different error message at the same line. Error: use of unsigned local variable. any idea please....:(

Wasif Hossain Over a year ago

@Ren please see my answer below. Thanks! please don't forget to accept and upvote the correct answers.

Ren Over a year ago

@SudhakarTillapudi It still prompt "input string not in correct format". Maybe it does not resize the GlobalDataClass array..correct me if im wrong...=(

Sudhakar Tillapudi Over a year ago

@Ren: assign it to null before assigning size to GlobalDataClass.dDataArray as GlobalDataClass.dDataArray=null;

|

Wasif Hossain · Accepted Answer · 2014-02-20 03:16:55Z

2

EDIT:

it seems that you are trying to copy the contents of arrayTemp to GlobalDataClass.dDataArray, but you are assigning values to GlobalDataClass.dDataArray, and trying to copy empty arrayTemp to GlobalDataClass.dDataArray.

So first declare the tempArray outside the for-loop and then populate it instead of GlobalDataClass.dDataArray inside the for-loop accordingly:

string filename = openFileDialog1.FileName;
string[] line = File.ReadAllLines(filename);

var arrayTemp = new double[line.Length, 2];

using (var reader2 = File.OpenText(@filename))
{
    for (int i = 0; i < line.Length; i++)
    {
        string lines = reader2.ReadLine();
        var data = lines.Split(',');
        arrayTemp[i, 0] = double.Parse(data[0]);
        arrayTemp[i, 1] = double.Parse(data[1]);
    }
    Array.Copy(arrayTemp, GlobalDataClass.dDataArray, line.Length); // now the error should go away.
}

EDIT 2:

you don't need to read the file 2nd time in the using() clause.

Now please try the following:

string filename = openFileDialog1.FileName;
string[] line = File.ReadAllLines(filename);

var arrayTemp = new double[line.Length, 2];

for (int i = 0; i < line.Length; i++)
{
    var data = line[i].Split(',');
    arrayTemp[i, 0] = double.Parse(data[0]);
    arrayTemp[i, 1] = double.Parse(data[1]);
}
Array.Copy(arrayTemp, GlobalDataClass.dDataArray, line.Length); // now the error should go away.

edited Feb 20, 2014 at 3:16

answered Feb 20, 2014 at 2:36

Wasif Hossain

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6 Comments

Ren Over a year ago

Wow,you even correct my mistakes. There's no error now, but the code resize doesn't work. It still prompt input string not in correct format whenever i load text file which have less length then my global class array..do you have any solution please?

Sudhakar Tillapudi Over a year ago

@Ren: you need to add this line -> GlobalDataClass.dDataArray=new double[line.Length,2]; after arrayTemp declaration, check my edited answer.

Wasif Hossain Over a year ago

@Ren please follow EDIT 2 in my answer

Ren Over a year ago

@WasifHossain I still have the same error: " input string not in correct format"..any idea please?

Ren Over a year ago

@SudhakarTillapudi thanks. But even if I add as you said. It still prompt "input string not in correct format"..

|

Cyral · Accepted Answer · 2014-02-20 02:41:57Z

Your tempArray is out of the scope of you Array.Copy because it is inside of your for loop, you need to move it into the scope of your method call so the method can access it. (Similar to how GlobalDataClass.dDataArray is declared elsewhere)

//Array is now declared in an accessible scop
double[,] arrayTemp;
string filename = openFileDialog1.FileName;
string[] line = File.ReadAllLines(filename);
using (var reader2 = File.OpenText(@filename))
{
    for (int i = 0; i < line.Length; i++)
    {
        string lines = reader2.ReadLine();
        arrayTemp = new double[line.Length, 2];
        var data = lines.Split(',');
        GlobalDataClass.dDataArray[i, 0] = double.Parse(data[0]);
        GlobalDataClass.dDataArray[i, 1] = double.Parse(data[1]);
    }
    Array.Copy(arrayTemp, GlobalDataClass.dDataArray, line.Length); //error the name "arrayTemp" does not exist in the current context.
}

Statements "deeper" into the { } hierarchy are only accessible to statements within them, and other child scopes in them. Parent scopes outside of the original brackets cannot access the variables.

Baahubali · Accepted Answer · 2014-02-20 02:34:54Z

1

looks like you array is out of scope because it's declared inside the for loop and you are trying to access it outside the for loop

answered Feb 20, 2014 at 2:34

Baahubali

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Comments

Gláucio Leonardo Sant'ana · Accepted Answer · 2018-05-17 12:09:16Z

0

I have answered on this link

To copy an array to another one, just use the "Clone()" function like the following:

This is your array list

object newArray = new object [row, column];

When you are creating another Array just use this code:

object[,] clonedArray = (object[,]) newArray.Clone();

Simple! Have fun!

answered May 17, 2018 at 12:09

Gláucio Leonardo Sant'ana

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