// define six ranges for column 1 to column 6, to store six variables in each file.
range a1 = [book1]sheet1!col(1);
range a2 = [book1]sheet1!col(2);
range a3 = [book1]sheet1!col(3);
range a4 = [book1]sheet1!col(4);
range a5 = [book1]sheet1!col(5);
range a6 = [book1]sheet1!col(6);

// loop from Book2 to Book n, variables in these books all are put to Book1.
for(ii=2;ii<n+1;ii++)
{
	range bo = [book$(ii)]; // define a range for Book ii.

	// define six ranges for column 1 to column 6 of Book ii.
	range b1 = [book$(ii)]sheet1!col(1);
	range b2 = [book$(ii)]sheet1!col(2);
	range b3 = [book$(ii)]sheet1!col(3);
	range b4 = [book$(ii)]sheet1!col(4);
	range b5 = [book$(ii)]sheet1!col(5);
	range b6 = [book$(ii)]sheet1!col(6);

	// put variables in Book ii to Book 1.
	a1[ii] = b1[1];
	a2[ii] = b2[1];
	a3[ii] = b3[1];
	a4[ii] = b4[1];
	a5[ii] = b5[1];
	a6[ii] = b6[1];
	delete bo; // delete Book ii.
}