关于用正确的数字值打印浮点数

Question

我有两个变量np.sum(train_y)和train_x.shape[0]。单独打印时，它们是：

print('np.sum(train_y) ',np.sum(train_y))
print('train_x.shape[0] ',train_x.shape[0])

('np.sum(train_y) ', 398)
('train_x.shape[0] ', 213605)

但是，它们的计算比率打印为0而不是0.00186。

print('np.sum(train_y)/train_x.shape[0]  ',np.sum(train_y)/train_x.shape[0])


('np.sum(train_y)/train_x.shape[0]  ', 0)

如何正确计算值？