《动手学深度学习》-3.5图像分类数据集
1.引用包
import numpy as np
import torch
import torchvision
from torch.utils import data
from torchvision import transforms#数据操作
import random
import matplotlib.pyplot as plt
import matplotlib
from torch.utils import data
from torch import nn
import d2l
import warnings
2.下载并获取图片数据集FashionMnist
arnings.filterwarnings('ignore')
trans = transforms.ToTensor() #把图片转成预处理,转成张量
mnist_train = torchvision.datasets.FashionMNIST(
root="D:\PycharmDocument\limu\data", train=True, transform=trans, download=True)
mnist_test = torchvision.datasets.FashionMNIST(
root="D:\PycharmDocument\limu\data", train=False, transform=trans, download=True)
获取图标y(简化形式)
def get_fashion_mnist_labels(labels):
text_labels=['t-shirt', 'trouser', 'pullover', 'dress', 'coat','sandal', 'shirt', 'sneaker', 'bag', 'ankle boot']
return text_labels[int(labels)]
图片显示(自制)
X,y=next(iter(data.DataLoader(mnist_train,batch_size=18)))
def show_image(X,y,num_rows,num_cols,scale=1.5):
figsize=[num_cols*scale,num_rows*scale]#画布大小
fig,axes=plt.subplots(num_rows,num_cols,figsize=figsize) #设置画布和子图
ax = axes.flatten() #对图片进行平展
for i in range(num_rows*num_cols):
ax[i].imshow(X[i].squeeze().numpy()) # 对第一个字图,展示第一个图片
ax[i].set(title=get_fashion_mnist_labels(y[i].item())) #对第一个字图设置标题
ax[i].set_xticks([])#清空x轴
ax[i].set_yticks([])#清空x轴
plt.tight_layout()#自动调整子图间距
plt.show()展示
图片显示(李沐)
def get_fashion_mnist_labels(labels): #@save
"""返回Fashion-MNIST数据集的文本标签"""
text_labels = ['t-shirt', 'trouser', 'pullover', 'dress', 'coat',
'sandal', 'shirt', 'sneaker', 'bag', 'ankle boot']
return [text_labels[int(i)] for i in labels]
def show_images(imgs, num_rows, num_cols, titles=None, scale=1.5): #@save """绘制图像列表"""
figsize = (num_cols * scale, num_rows * scale)#画布大小
_, axes = d2l.plt.subplots(num_rows, num_cols, figsize=figsize)#画布和子图大小
axes = axes.flatten()#子图平展
for i, (ax, img) in enumerate(zip(axes, imgs)): #对子图和图对应起来,并依次取出
if torch.is_tensor(img):
# 图片张量
ax.imshow(img.numpy()) #如果是张量,以numpy形式展示
else:
# PIL图片
ax.imshow(img)
ax.axes.get_xaxis().set_visible(False) #去除x轴
ax.axes.get_yaxis().set_visible(False)
if titles:
ax.set_title(titles[i])
return axes
X, y = next(iter(data.DataLoader(mnist_train, batch_size=18)))
show_images(X.reshape(18, 28, 28), 2, 9, titles=get_fashion_mnist_labels(y));
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