替换数据框列中的特定值

时间:2018-11-02 09:27:33

标签: python pandas dataframe

我正在jupyter笔记本中运行以下代码,该代码检查nametest_df['text']中的文本字符串并返回人员名称。我设法解决了这个问题,并希望将这些名称推到nametest_df['name']内的各个字段中,当前所有值均为NaN

我尝试了Series.replace()方法,但是“名称”列中的所有条目都显示相同的名称。

有什么线索可以有效地做到这一点吗?

for word in nametest_df['text']:

    for sent in nltk.sent_tokenize(word):
        tokens = nltk.tokenize.word_tokenize(sent)
        tags = st.tag(tokens)

        for tag in tags:
            if tag[1]=='PERSON':
                name = tag[0]
                print(name)

    nametest_df.name = nametest_df.name.replace({"NaN": name})

样品名称test_df

      **text**                    **name**
0   His name is John                NaN
1   I went to the beach             NaN
2   My friend is called Fred        NaN

预期产量

      **text**                    **name**
0   His name is John                John                
1   I went to the beach             NaN
2   My friend is called Fred        Fred      

1 个答案:

答案 0 :(得分:1)

请勿尝试一一填写序列值。这是低效率的,容易出错。一个更好的主意是创建一个名称的列表并直接分配。

L = []
for word in nametest_df['text']:
    for sent in nltk.sent_tokenize(word):
        tokens = nltk.tokenize.word_tokenize(sent)
        tags = st.tag(tokens)
        for tag in tags:
            if tag[1]=='PERSON':
                L.append(tag[0])

nametest_df.loc[nametest_df['name'].isnull(), 'name'] = L