How to add a row to dataframe in a for loop

>df = DataFrame(columns=('lib', 'qty1', 'qty2'))    for i in range(5):      df.loc[i] = [randint(-1,1) for n in range(3)]  >print(df)     lib  qty1  qty2 0    0     0    -1 1   -1    -1     1 2    1    -1     1 3    0     0     0 4    1    -1    -1  [5 rows x 3 columns]