why all Tk.Button get last index number?

Question

In this case, all button has last index value.

I hope to know why all button has last index.

def printIndex(row, col):
    print("index = %d, %d" %(row,col))

def makeBoard(row, col):
    window = Tk()

    btlist = [0 for i in range(row)]
    for i in range(row):
        btlist[i] = [0 for j in range(col)]

    for i in range(row):
        for j in range(col):
            btlist[i][j] = Button(window, text="a", command = lambda : printIndex(i, j))
            btlist[i][j].grid(row=i,column=j)

makeBoard(5, 3)