在上面几个实战中,我们使用的是Pytorch官方准备好的FashionMNIST数据集进行的训练与测试。本篇博文介绍我们如何自己去准备数据集,以应对更多的场景。
我们此次使用的是猫狗大战数据集,开始之前我们要先把数据处理一下,形式如下
datas │ └───train │ │ │ └───cats │ │ │ cat1000.jpg │ │ │ cat1001.jpg │ │ │ … │ └───dogs │ │ │ dog1000.jpg │ │ │ dog1001.jpg │ │ │ … └───valid │ │ │ └───cats │ │ │ cat0.jpg │ │ │ cat1.jpg │ │ │ … │ └───dogs │ │ │ dog0.jpg │ │ │ dog1.jpg │ │ │ …
train数据集中有23000张数据,valid数据集中有2000数据用于验证网络性能
代码部分 1.采用隐形字典形式,代码简练,不易理解
import torch as t
import torchvision as tv
import os
data_dir = "./datas"
BATCH_SIZE = 100
EPOCH = 10
transform = {
x:tv.transforms.Compose(
[tv.transforms.Resize([64,64]),tv.transforms.ToTensor()]#tv.transforms.Resize 用于重设图片大小
)
for x in ["train","valid"]
}
datasets = {
x:tv.datasets.ImageFolder(root = os.path.join(data_dir,x),transform=transform[x])
for x in ["train","valid"]
}
dataloader = {
x:t.utils.data.DataLoader(dataset= datasets[x],
batch_size=BATCH_SIZE,
shuffle=True
)
for x in ["train","valid"]
}
b_x,b_y = next(iter(dataloader["train"]))
print(b_x.shape,b_y.shape)
index_classes = datasets["train"].class_to_idx
print(index_classes)
2.采用显性字典形式,代码稍多,易于理解
import torch as t
import torchvision as tv
data_dir = "./datas"
BATCH_SIZE = 100
EPOCH = 10
transform = {
"train":tv.transforms.Compose(
[tv.transforms.Resize([64,64]),tv.transforms.ToTensor()]
),
"valid":tv.transforms.Compose(
[tv.transforms.Resize([64,64]),tv.transforms.ToTensor()]
),
}
datasets = {
"train":tv.datasets.ImageFolder(root = os.path.join(data_dir,"train"),transform=transform["train"]),
"vaild":tv.datasets.ImageFolder(root = os.path.join(data_dir,"vaild"),transform=transform["vaild"]),
}
dataloader = {
"train":t.utils.data.DataLoader(dataset= datasets["train"],
batch_size=BATCH_SIZE,
shuffle=True
),
"valid":t.utils.data.DataLoader(dataset= datasets["valid"],
batch_size=100,
shuffle=True
)
}
b_x,b_y = next(iter(dataloader["train"]))
print(b_x.shape,b_y.shape)
index_classes = datasets["train"].class_to_idx
print(index_classes)
输出结果
torch.Size([100, 3, 64, 64]) torch.Size([100])
{'cats': 0, 'dogs': 1}