赛题背景

对于当时的Quora网站来说，存在的主要问题是如何处理有毒和分裂性的内容，Quora希望解决这个问题，使平台成为一个让用户可以放心与世界分享知识的地方。
在本次比赛中，希望参赛选手开发算法能识别并检测到Quora中有害和误导的内容。

赛题评价指标

二分类问题，使用f1-score进行评价
对于测试集的样本，需要预测对应的概率值。并与真是的标签进行评价

数据集分析

train_df = pd.read_csv("../input/train.csv")
test_df = pd.read_csv("../input/test.csv")
print("Train shape : ", train_df.shape)
print("Test shape : ", test_df.shape)
train_df.head()

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## target count ##
cnt_srs = train_df['target'].value_counts()
trace = go.Bar(
    x=cnt_srs.index,
    y=cnt_srs.values,
    marker=dict(
        color=cnt_srs.values,
        colorscale = 'Picnic',
        reversescale = True
    ),
)

layout = go.Layout(
    title='Target Count',
    font=dict(size=18)
)

data = [trace]
fig = go.Figure(data=data, layout=layout)
py.iplot(fig, filename="TargetCount")

## target distribution ##
labels = (np.array(cnt_srs.index))
sizes = (np.array((cnt_srs / cnt_srs.sum())*100))

trace = go.Pie(labels=labels, values=sizes)
layout = go.Layout(
    title='Target distribution',
    font=dict(size=18),
    width=600,
    height=600,
)
data = [trace]
fig = go.Figure(data=data, layout=layout)
py.iplot(fig, filename="usertype")

在这里插入图片描述
target=1是指不好的问题，大概占总数据集的94%
target=0是指好的问题，大概占总数据集的6%
Word Cloud

from wordcloud import WordCloud, STOPWORDS

# Thanks : https://www.kaggle.com/aashita/word-clouds-of-various-shapes ##
def plot_wordcloud(text, mask=None, max_words=200, max_font_size=100, figure_size=(24.0,16.0), 
                   title = None, title_size=40, image_color=False):
    stopwords = set(STOPWORDS)
    more_stopwords = {'one', 'br', 'Po', 'th', 'sayi', 'fo', 'Unknown'}
    stopwords = stopwords.union(more_stopwords)

    wordcloud = WordCloud(background_color='black',
                    stopwords = stopwords,
                    max_words = max_words,
                    max_font_size = max_font_size, 
                    random_state = 42,
                    width=800, 
                    height=400,
                    mask = mask)
    wordcloud.generate(str(text))
    
    plt.figure(figsize=figure_size)
    if image_color:
        image_colors = ImageColorGenerator(mask);
        plt.imshow(wordcloud.recolor(color_func=image_colors), interpolation="bilinear");
        plt.title(title, fontdict={'size': title_size,  
                                  'verticalalignment': 'bottom'})
    else:
        plt.imshow(wordcloud);
        plt.title(title, fontdict={'size': title_size, 'color': 'black', 
                                  'verticalalignment': 'bottom'})
    plt.axis('off');
    plt.tight_layout()  
    
plot_wordcloud(train_df["question_text"], title="Word Cloud of Questions")

在这里插入图片描述
正向词汇出现的频率比较高
正向情感分本和反向情感文本出现的单词频率：

from collections import defaultdict
train1_df = train_df[train_df["target"]==1]
train0_df = train_df[train_df["target"]==0]

## custom function for ngram generation ##
def generate_ngrams(text, n_gram=1):
    token = [token for token in text.lower().split(" ") if token != "" if token not in STOPWORDS]
    ngrams = zip(*[token[i:] for i in range(n_gram)])
    return [" ".join(ngram) for ngram in ngrams]

## custom function for horizontal bar chart ##
def horizontal_bar_chart(df, color):
    trace = go.Bar(
        y=df["word"].values[::-1],
        x=df["wordcount"].values[::-1],
        showlegend=False,
        orientation = 'h',
        marker=dict(
            color=color,
        ),
    )
    return trace

## Get the bar chart from sincere questions ##
freq_dict = defaultdict(int)
for sent in train0_df["question_text"]:
    for word in generate_ngrams(sent):
        freq_dict[word] += 1
fd_sorted = pd.DataFrame(sorted(freq_dict.items(), key=lambda x: x[1])[::-1])
fd_sorted.columns = ["word", "wordcount"]
trace0 = horizontal_bar_chart(fd_sorted.head(50), 'blue')

## Get the bar chart from insincere questions ##
freq_dict = defaultdict(int)
for sent in train1_df["question_text"]:
    for word in generate_ngrams(sent):
        freq_dict[word] += 1
fd_sorted = pd.DataFrame(sorted(freq_dict.items(), key=lambda x: x[1])[::-1])
fd_sorted.columns = ["word", "wordcount"]
trace1 = horizontal_bar_chart(fd_sorted.head(50), 'blue')

# Creating two subplots
fig = tools.make_subplots(rows=1, cols=2, vertical_spacing=0.04,
                          subplot_titles=["Frequent words of sincere questions", 
                                          "Frequent words of insincere questions"])
fig.append_trace(trace0, 1, 1)
fig.append_trace(trace1, 1, 2)
fig['layout'].update(height=1200, width=900, paper_bgcolor='rgb(233,233,233)', title="Word Count Plots")
py.iplot(fig, filename='word-plots')

在这里插入图片描述

Bigram Count Plots (两个单词组成的词组的词语对排序)

freq_dict = defaultdict(int)
for sent in train0_df["question_text"]:
    for word in generate_ngrams(sent,2):
        freq_dict[word] += 1
fd_sorted = pd.DataFrame(sorted(freq_dict.items(), key=lambda x: x[1])[::-1])
fd_sorted.columns = ["word", "wordcount"]
trace0 = horizontal_bar_chart(fd_sorted.head(50), 'orange')


freq_dict = defaultdict(int)
for sent in train1_df["question_text"]:
    for word in generate_ngrams(sent,2):
        freq_dict[word] += 1
fd_sorted = pd.DataFrame(sorted(freq_dict.items(), key=lambda x: x[1])[::-1])
fd_sorted.columns = ["word", "wordcount"]
trace1 = horizontal_bar_chart(fd_sorted.head(50), 'orange')

# Creating two subplots
fig = tools.make_subplots(rows=1, cols=2, vertical_spacing=0.04,horizontal_spacing=0.15,
                          subplot_titles=["Frequent bigrams of sincere questions", 
                                          "Frequent bigrams of insincere questions"])
fig.append_trace(trace0, 1, 1)
fig.append_trace(trace1, 1, 2)
fig['layout'].update(height=1200, width=900, paper_bgcolor='rgb(233,233,233)', title="Bigram Count Plots")
py.iplot(fig, filename='word-plots')

在这里插入图片描述
Trigram Count Plots 三个单词组成的词组出现的频率排序

freq_dict = defaultdict(int)
for sent in train0_df["question_text"]:
    for word in generate_ngrams(sent,3):
        freq_dict[word] += 1
fd_sorted = pd.DataFrame(sorted(freq_dict.items(), key=lambda x: x[1])[::-1])
fd_sorted.columns = ["word", "wordcount"]
trace0 = horizontal_bar_chart(fd_sorted.head(50), 'green')


freq_dict = defaultdict(int)
for sent in train1_df["question_text"]:
    for word in generate_ngrams(sent,3):
        freq_dict[word] += 1
fd_sorted = pd.DataFrame(sorted(freq_dict.items(), key=lambda x: x[1])[::-1])
fd_sorted.columns = ["word", "wordcount"]
trace1 = horizontal_bar_chart(fd_sorted.head(50), 'green')

# Creating two subplots
fig = tools.make_subplots(rows=1, cols=2, vertical_spacing=0.04, horizontal_spacing=0.2,
                          subplot_titles=["Frequent trigrams of sincere questions", 
                                          "Frequent trigrams of insincere questions"])
fig.append_trace(trace0, 1, 1)
fig.append_trace(trace1, 1, 2)
fig['layout'].update(height=1200, width=1200, paper_bgcolor='rgb(233,233,233)', title="Trigram Count Plots")
py.iplot(fig, filename='word-plots')

在这里插入图片描述

## Number of words in the text ##
train_df["num_words"] = train_df["question_text"].apply(lambda x: len(str(x).split()))
test_df["num_words"] = test_df["question_text"].apply(lambda x: len(str(x).split()))

## Number of unique words in the text ##
train_df["num_unique_words"] = train_df["question_text"].apply(lambda x: len(set(str(x).split())))
test_df["num_unique_words"] = test_df["question_text"].apply(lambda x: len(set(str(x).split())))

## Number of characters in the text ##
train_df["num_chars"] = train_df["question_text"].apply(lambda x: len(str(x)))
test_df["num_chars"] = test_df["question_text"].apply(lambda x: len(str(x)))

## Number of stopwords in the text ##
train_df["num_stopwords"] = train_df["question_text"].apply(lambda x: len([w for w in str(x).lower().split() if w in STOPWORDS]))
test_df["num_stopwords"] = test_df["question_text"].apply(lambda x: len([w for w in str(x).lower().split() if w in STOPWORDS]))

## Number of punctuations in the text ##
train_df["num_punctuations"] =train_df['question_text'].apply(lambda x: len([c for c in str(x) if c in string.punctuation]) )
test_df["num_punctuations"] =test_df['question_text'].apply(lambda x: len([c for c in str(x) if c in string.punctuation]) )

## Number of title case words in the text ##
train_df["num_words_upper"] = train_df["question_text"].apply(lambda x: len([w for w in str(x).split() if w.isupper()]))
test_df["num_words_upper"] = test_df["question_text"].apply(lambda x: len([w for w in str(x).split() if w.isupper()]))

## Number of title case words in the text ##
train_df["num_words_title"] = train_df["question_text"].apply(lambda x: len([w for w in str(x).split() if w.istitle()]))
test_df["num_words_title"] = test_df["question_text"].apply(lambda x: len([w for w in str(x).split() if w.istitle()]))

## Average length of the words in the text ##
train_df["mean_word_len"] = train_df["question_text"].apply(lambda x: np.mean([len(w) for w in str(x).split()]))
test_df["mean_word_len"] = test_df["question_text"].apply(lambda x: np.mean([len(w) for w in str(x).split()]))

## Truncate some extreme values for better visuals ##
train_df['num_words'].loc[train_df['num_words']>60] = 60 #truncation for better visuals
train_df['num_punctuations'].loc[train_df['num_punctuations']>10] = 10 #truncation for better visuals
train_df['num_chars'].loc[train_df['num_chars']>350] = 350 #truncation for better visuals

f, axes = plt.subplots(3, 1, figsize=(10,20))
sns.boxplot(x='target', y='num_words', data=train_df, ax=axes[0])
axes[0].set_xlabel('Target', fontsize=12)
axes[0].set_title("Number of words in each class", fontsize=15)

sns.boxplot(x='target', y='num_chars', data=train_df, ax=axes[1])
axes[1].set_xlabel('Target', fontsize=12)
axes[1].set_title("Number of characters in each class", fontsize=15)

sns.boxplot(x='target', y='num_punctuations', data=train_df, ax=axes[2])
axes[2].set_xlabel('Target', fontsize=12)
#plt.ylabel('Number of punctuations in text', fontsize=12)
axes[2].set_title("Number of punctuations in each class", fontsize=15)
plt.show()

在这里插入图片描述

可以看到负面文本的单词量、标点符号、词汇量是比较多的，因为负面文本的数据集比较多

pytorch建模

由于不熟悉pytorch，这里只是做了代码思路的学习，并没有实践

# 所有的seed，保证结果可付现
# 参数初始化
# 数据划分方法
# 数据扩增方法
def seed_torch(seed=1029):
    random.seed(seed)
    os.environ['PYTHONHASHSEED'] = str(seed)
    np.random.seed(seed)
    torch.manual_seed(seed)
    torch.cuda.manual_seed(seed)
    torch.backends.cudnn.deterministic = True
   
train["target"].value_counts()