out = np.array(torch.max(out_tensor.data, 1)[1].squeeze().cpu())
时间: 2024-05-29 18:16:01 浏览: 14
这行代码的作用是从一个PyTorch的tensor中获取每个batch中预测结果的最大值,并将结果存储在一个numpy数组中。具体来说,它首先使用`torch.max()`函数在第二个维度上计算每个batch中预测结果的最大值和相应的索引值,然后使用`squeeze()`函数去除维度为1的维度,最后使用`cpu()`函数将结果从GPU转移到CPU上,并将结果存储在一个numpy数组中。
相关问题
根据提供的data.csv 附件(comment、star),用python语言对外卖评论进行分类,2分类,正向负向,两种方式:sklearn调用以及自己编写模型类。根据分类结果,分别画出正向词云图,负向词云图
好的,我会尽力回答你的问题。首先需要说明的是,我们需要在进行分类前对评论数据进行预处理,包括去除停用词、分词、词性标注等。这里我将使用Python中的nltk库进行预处理。
首先,我们需要安装nltk库,可以通过以下命令进行安装:
```python
!pip install nltk
```
安装完成后,我们可以通过以下代码对评论数据进行预处理:
```python
import pandas as pd
import nltk
from nltk.corpus import stopwords
from nltk.tokenize import word_tokenize
from nltk.stem import WordNetLemmatizer
# 下载停用词
nltk.download('stopwords')
# 下载punkt
nltk.download('punkt')
# 下载wordnet
nltk.download('wordnet')
# 读取评论数据
data = pd.read_csv('data.csv')
# 定义停用词
stop_words = set(stopwords.words('english'))
# 初始化词性还原器
wordnet_lemmatizer = WordNetLemmatizer()
# 定义预处理函数
def preprocess(text):
# 分词
words = word_tokenize(text.lower())
# 去除停用词
words = [word for word in words if word not in stop_words]
# 词性还原
words = [wordnet_lemmatizer.lemmatize(word, pos='v') for word in words]
# 返回预处理后的评论
return " ".join(words)
# 对评论进行预处理
data['comment'] = data['comment'].apply(preprocess)
```
接下来,我们可以使用sklearn库中的TfidfVectorizer对评论进行特征提取,并使用LogisticRegression进行分类。具体代码如下:
```python
from sklearn.feature_extraction.text import TfidfVectorizer
from sklearn.linear_model import LogisticRegression
from sklearn.metrics import classification_report
# 定义特征提取器
vectorizer = TfidfVectorizer()
# 提取特征
X = vectorizer.fit_transform(data['comment'])
# 定义标签
y = data['star'].apply(lambda x: 1 if x > 3 else 0)
# 划分训练集和测试集
train_size = int(len(data) * 0.8)
X_train, X_test, y_train, y_test = X[:train_size], X[train_size:], y[:train_size], y[train_size:]
# 定义分类器
clf = LogisticRegression()
# 训练分类器
clf.fit(X_train, y_train)
# 对测试集进行预测
y_pred = clf.predict(X_test)
# 输出分类报告
print(classification_report(y_test, y_pred))
```
除了使用sklearn库外,我们也可以自己编写模型类进行分类。这里我将使用PyTorch框架来编写模型类。具体代码如下:
```python
import torch
from torch import nn
from torch.utils.data import Dataset, DataLoader
from sklearn.metrics import classification_report
# 定义评论数据集类
class CommentDataset(Dataset):
def __init__(self, data, vectorizer):
self.data = data
self.vectorizer = vectorizer
def __len__(self):
return len(self.data)
def __getitem__(self, index):
comment = self.data.iloc[index]['comment']
star = self.data.iloc[index]['star']
features = self.vectorizer.transform([comment]).toarray().squeeze()
label = 1 if star > 3 else 0
return torch.Tensor(features), torch.Tensor([label])
# 定义分类模型类
class Classifier(nn.Module):
def __init__(self, input_size):
super(Classifier, self).__init__()
self.fc1 = nn.Linear(input_size, 128)
self.fc2 = nn.Linear(128, 64)
self.fc3 = nn.Linear(64, 2)
self.relu = nn.ReLU()
self.dropout = nn.Dropout(p=0.5)
def forward(self, x):
x = self.fc1(x)
x = self.relu(x)
x = self.dropout(x)
x = self.fc2(x)
x = self.relu(x)
x = self.dropout(x)
x = self.fc3(x)
return x
# 定义特征提取器
vectorizer = TfidfVectorizer()
# 定义评论数据集
dataset = CommentDataset(data, vectorizer)
# 划分训练集和测试集
train_size = int(len(data) * 0.8)
train_dataset, test_dataset = torch.utils.data.random_split(dataset, [train_size, len(dataset) - train_size])
train_loader = DataLoader(train_dataset, batch_size=32, shuffle=True)
test_loader = DataLoader(test_dataset, batch_size=32, shuffle=False)
# 初始化分类器
classifier = Classifier(input_size=train_dataset[0][0].shape[0])
# 定义优化器和损失函数
optimizer = torch.optim.Adam(classifier.parameters(), lr=0.001)
criterion = nn.CrossEntropyLoss()
# 训练分类器
for epoch in range(10):
for features, labels in train_loader:
optimizer.zero_grad()
outputs = classifier(features)
loss = criterion(outputs, labels.long())
loss.backward()
optimizer.step()
# 在测试集上进行评估
y_true = []
y_pred = []
with torch.no_grad():
for features, labels in test_loader:
outputs = classifier(features)
_, predicted = torch.max(outputs.data, 1)
y_true.extend(labels.numpy())
y_pred.extend(predicted.numpy())
print(classification_report(y_true, y_pred))
```
接下来,我们可以根据分类结果,分别画出正向词云图和负向词云图。具体代码如下:
```python
from wordcloud import WordCloud
import matplotlib.pyplot as plt
import numpy as np
from PIL import Image
# 定义正向评论和负向评论
positive_comments = data[data['star'] > 3]['comment']
negative_comments = data[data['star'] <= 3]['comment']
# 定义正向词云图
positive_text = " ".join(positive_comments)
mask = np.array(Image.open('positive.png'))
wc = WordCloud(background_color='white', mask=mask)
wc.generate(positive_text)
plt.imshow(wc, interpolation='bilinear')
plt.axis('off')
plt.show()
# 定义负向词云图
negative_text = " ".join(negative_comments)
mask = np.array(Image.open('negative.png'))
wc = WordCloud(background_color='white', mask=mask)
wc.generate(negative_text)
plt.imshow(wc, interpolation='bilinear')
plt.axis('off')
plt.show()
```
这里需要注意的是,我们需要准备好正向词云图和负向词云图的模板图片(例如positive.png和negative.png),用于生成相应形状的词云图。
使用循环神经网络学习汉语拼音的拼写,本次实验重点为准备数据和模型。 1、拼音数据(无声调):/kaggle/input/pyinin/pinyn.txt 2、定义数据集:采用字符模型,因此一个字符为一个样本。每个样本采用one-hot编码。 3、样本是时间相关的,分别实现序列的随机采样和序列的顺序划分 4、标签Y与X同形状,但时间超前1 5、准备数据:一次梯度更新使用的数据形状为:(时间步,Batch,类别数) 6、实现基本循环神经网络模型 (1)循环单元为nn.RNN或GRU (2)输出层的全连接使用RNN所有时间步的输出 (3)隐状态初始值为0 (4)测试前向传播 (5)如果采用顺序划分,需梯度截断 7、训练:损失函数为平均交叉熵 8、预测:给定一个前缀,进行单步预测和K步预测。按照每一小题输出每段python代码
好的,以下是每一小题对应的Python代码:
1. 读取拼音数据(无声调):
```python
with open('/kaggle/input/pyinin/pinyn.txt', 'r', encoding='utf-8') as f:
pinyin_data = f.read().split()
```
2. 定义数据集,采用字符模型,每个样本采用one-hot编码:
```python
import numpy as np
# 构建字符集
vocab = sorted(set(''.join(pinyin_data)))
vocab_size = len(vocab)
# 创建字符到索引的映射
char_to_idx = {char: idx for idx, char in enumerate(vocab)}
idx_to_char = np.array(vocab)
# 将拼音数据转换为one-hot编码
def one_hot_encode(text, vocab_size, char_to_idx):
num_samples = len(text)
max_len = max([len(txt) for txt in text])
input_data = np.zeros((num_samples, max_len, vocab_size))
for i in range(num_samples):
for j in range(len(text[i])):
input_data[i, j, char_to_idx[text[i][j]]] = 1
return input_data
input_data = one_hot_encode(pinyin_data, vocab_size, char_to_idx)
```
3. 实现序列的随机采样和序列的顺序划分:
```python
# 随机采样
def random_sample(batch_size, seq_len):
# 随机选择一个起始位置
idx = np.random.randint(0, input_data.shape[0] - seq_len)
input_seq = input_data[idx:idx+seq_len]
target_seq = np.copy(input_seq)
target_seq[:-1] = input_seq[1:]
return input_seq, target_seq
# 序列的顺序划分
def seq_partition(batch_size, seq_len):
num_batches = input_data.shape[0] // (batch_size * seq_len)
data = input_data[:num_batches * batch_size * seq_len]
data = data.reshape(batch_size, num_batches * seq_len, vocab_size)
data = np.transpose(data, axes=[1, 0, 2])
input_seq = data[:-1]
target_seq = data[1:]
return input_seq, target_seq
```
4. 标签Y与X同形状,但时间超前1:
```python
target_seq = np.copy(input_seq)
target_seq[:-1] = input_seq[1:]
```
5. 准备数据,一次梯度更新使用的数据形状为:(时间步,Batch,类别数):
```python
def get_data(batch_size, seq_len, use_random_sample=True):
if use_random_sample:
X, Y = random_sample(batch_size, seq_len)
else:
X, Y = seq_partition(batch_size, seq_len)
return X.transpose(1, 0, 2), Y.transpose(1, 0, 2)
```
6. 实现基本循环神经网络模型:
```python
import torch
import torch.nn as nn
class RNNModel(nn.Module):
def __init__(self, vocab_size, hidden_size, num_layers=1, rnn_type='rnn'):
super().__init__()
self.rnn_type = rnn_type
self.hidden_size = hidden_size
self.num_layers = num_layers
self.embedding = nn.Embedding(vocab_size, hidden_size)
if rnn_type == 'rnn':
self.rnn = nn.RNN(hidden_size, hidden_size, num_layers)
elif rnn_type == 'gru':
self.rnn = nn.GRU(hidden_size, hidden_size, num_layers)
self.fc = nn.Linear(hidden_size, vocab_size)
def forward(self, input_seq, hidden=None):
seq_len, batch_size, _ = input_seq.size()
if hidden is None:
hidden = self.init_hidden(batch_size)
embed = self.embedding(input_seq)
output, hidden = self.rnn(embed, hidden)
output = output.view(seq_len * batch_size, self.hidden_size)
output = self.fc(output)
return output.view(seq_len, batch_size, -1), hidden
def init_hidden(self, batch_size):
if self.rnn_type == 'gru':
return torch.zeros(self.num_layers, batch_size, self.hidden_size)
else:
return torch.zeros(self.num_layers, batch_size, self.hidden_size)
```
7. 训练,损失函数为平均交叉熵:
```python
def train(model, optimizer, criterion, num_epochs, batch_size, seq_len):
model.train()
for epoch in range(num_epochs):
hidden = None
for i in range(0, input_data.shape[0] - seq_len, seq_len):
X, Y = get_data(batch_size, seq_len, use_random_sample=False)
X = torch.tensor(X, dtype=torch.long)
Y = torch.tensor(Y, dtype=torch.long)
optimizer.zero_grad()
output, hidden = model(X, hidden)
hidden.detach_()
loss = criterion(output.view(-1, vocab_size), Y.view(-1))
loss.backward()
nn.utils.clip_grad_norm_(model.parameters(), 0.5)
optimizer.step()
if epoch % 10 == 0:
print(f'Epoch {epoch}, Loss: {loss.item():.4f}')
```
8. 预测,给定一个前缀,进行单步预测和K步预测:
```python
def predict(model, init_text, predict_len):
hidden = None
input_seq = torch.tensor([[char_to_idx[c] for c in init_text]], dtype=torch.long)
output_text = init_text
for i in range(predict_len):
output, hidden = model(input_seq, hidden)
output = output[-1].squeeze(0)
output_dist = nn.functional.softmax(output, dim=0)
top_k_prob, top_k_idx = output_dist.topk(k=5)
top_k_prob = top_k_prob.detach().numpy()
top_k_idx = top_k_idx.detach().numpy()
for j in range(top_k_idx.shape[0]):
next_char = idx_to_char[top_k_idx[j]]
prob = top_k_prob[j]
output_text += next_char
input_seq = torch.tensor([[char_to_idx[c] for c in output_text]], dtype=torch.long)
return output_text
```
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