填充二维数组的最佳方法是什么？

Question

I am trying to fill an array using data from a database (Access), but when I run this code:

with dmSUPREMEDATA do
begin
  iNumberofRecords := ADOComplete.RecordCount;
  ADOComplete.First;
  SetLength(ArrSummary, iNumberofRecords, 3);
  for i := 0 to iNumberofRecords do
  begin
    ArrSummary[i, 0] := ADOComplete['Names'];
    ArrSummary[i, 1] := ADOComplete['Surnames'];
    ArrSummary[i, 2] := ADOComplete['Average'];
    ADOComplete.Next;
  end;
end;

This is the error that pops up:

Is there a better way to fill the array? This is coded with delphi

Answer 1

Your loop is going out out bounds of the array.

The 1st dimension of the array has iNumberofRecords number of elements, so it has valid indexes 0..iNumberofRecords-1 . The indexes that a for loop uses are inclusive , so you are looping through indexes 0..iNumberofRecords , which means the final iteration of the loop is accessing an invalid index.

You need to subtract -1 from the loop counter, eg:

for i := 0 to iNumberofRecords-1 do

or:

for i := 0 to Pred(iNumberofRecords) do

Answer 2

You can try create two for loops. Like a detail and subdetail, being one for the first array and other for the second.

var arr2d := array of array of string;

SetLength(arr2d, 5, 5);

for var i := 0 to Length(arr2d) - 1 do
begin
  for var j := 0 to Length(arr2d) - 1 do
    arr2d[i][j] := 'Text [' + i.ToString + '][' + j.toString + ']';
end