Python | enumerate() 函数_enumerate(loader)

用来添加一个索引

>>>seasons = ['Spring', 'Summer', 'Fall', 'Winter']
>>> list(enumerate(seasons))
[(0, 'Spring'), (1, 'Summer'), (2, 'Fall'), (3, 'Winter')]
>>> list(enumerate(seasons, start=1))       # 下标从 1 开始
[(1, 'Spring'), (2, 'Summer'), (3, 'Fall'), (4, 'Winter')]

比如循环

>>>seq = ['one', 'two', 'three']
>>> for i, element in enumerate(seq):
...     print i, element
... 
0 one
1 two
2 three

深度学习批量学习

step就是索引

for epoch in range(3):
    for step, (batch_x, batch_y) in enumerate(loader):
        # 训练
        print('Epoch: ', epoch, '| Step: ', step, '| batch x: ',
              batch_x.numpy(), '| batch y: ', batch_y.numpy())