10980

2Darray to 1darray with for loop

Question:

I know this is a very basic question, but I'm just new to programming and I think I'am struggling with a very simple issue... but here we go :p

In my app I have an array of arrays like this storing data retrieved from a mysql database.

data_array[][] 0001 | data1 | data2 | data3 | data4 | data5 0002 | data1 | data2 | data3 | data4 | data5 ... ... and so on.

Now in my app, I need to retrieve for each of the rows the first of the colums, ending with something like :

array { 0001, 0002}

I know doing ' for iterations ' I can retrieve all the data:

public String[] itarray{ int cols = 5; String[] xFINAL; for (int i=0 ; i < data_array; i++) { for (int j=0; j < cols; j++){ xFINAL = data_array[i]; System.out.println("1" + data_array[i][0]); } System.out.println(" "); } return xFINAL;}

But how can I get the first column for each of the rows? I tried with something like:

int j=0; for (int i = 0; i < data_array ; i++){ xFINAL[j] = data_array [i][0]; j++; }

But it's giving me a null pointer. How could I do this please?

Thanks in advance.

Answer1:

String[] xFINAL = new String[data_array.length]; int k =0; for (int i=0 ; i < data_array; i++) { array[k++] = data_array[i][0]; }

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