无法在正则表达式和 nltk 的帮助下删除特殊字符
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【中文标题】无法在正则表达式和 nltk 的帮助下删除特殊字符【英文标题】:Unable to remove special characters with the help of regex with nltk 【发布时间】:2021-07-21 15:50:47 【问题描述】:无法在 nltk 的正则表达式的帮助下删除特殊字符。
代码是
X, y = data.comments, data.sentiment
紧随其后
documents = []
from nltk.stem import WordNetLemmatizer
stemmer = WordNetLemmatizer()
for sen in range(0, len(X)):
# Remove all the special characters
document = re.sub(r'\W', ' ', str(X[sen]))
# remove all single characters
document = re.sub(r'\s+[a-zA-Z]\s+', ' ', document)
# Remove single characters from the start
document = re.sub(r'\^[a-zA-Z]\s+', ' ', document)
# Substituting multiple spaces with single space
document = re.sub(r'\s+', ' ', document, flags=re.I)
# Removing prefixed 'b'
document = re.sub(r'^b\s+', '', document)
# Converting to Lowercase
document = document.lower()
# Lemmatization
document = document.split()
document = [stemmer.lemmatize(word) for word in document]
document = ' '.join(document)
documents.append(document)
它返回的错误如下所示
KeyError Traceback (most recent call last)
~\anaconda3\lib\site-packages\pandas\core\indexes\base.py in get_loc(self, key, method, tolerance)
3079 try:
-> 3080 return self._engine.get_loc(casted_key)
3081 except KeyError as err:
pandas\_libs\index.pyx in pandas._libs.index.IndexEngine.get_loc()
pandas\_libs\index.pyx in pandas._libs.index.IndexEngine.get_loc()
pandas\_libs\hashtable_class_helper.pxi in pandas._libs.hashtable.Int64HashTable.get_item()
pandas\_libs\hashtable_class_helper.pxi in pandas._libs.hashtable.Int64HashTable.get_item()
KeyError: 9
The above exception was the direct cause of the following exception:
KeyError Traceback (most recent call last)
<ipython-input-16-f9320c54a8cb> in <module>
7 for sen in range(0, len(X)):
8 # Remove all the special characters
----> 9 document = re.sub(r'\W', ' ', str(X[sen]))
10
11 # remove all single characters
~\anaconda3\lib\site-packages\pandas\core\series.py in __getitem__(self, key)
822
823 elif key_is_scalar:
--> 824 return self._get_value(key)
825
826 if is_hashable(key):
~\anaconda3\lib\site-packages\pandas\core\series.py in _get_value(self, label, takeable)
930
931 # Similar to Index.get_value, but we do not fall back to positional
--> 932 loc = self.index.get_loc(label)
933 return self.index._get_values_for_loc(self, loc, label)
934
~\anaconda3\lib\site-packages\pandas\core\indexes\base.py in get_loc(self, key, method, tolerance)
3080 return self._engine.get_loc(casted_key)
3081 except KeyError as err:
-> 3082 raise KeyError(key) from err
3083
3084 if tolerance is not None:
KeyError: 9
我不知道为什么它不起作用,仅删除特殊字符代码不起作用。我正在尝试清理数据,目标变量是 y,问题案例是二进制分类。仅删除特殊字符不起作用。
【问题讨论】:
尝试使用iloc
索引而不是纯切片:document = re.sub(r'\W', ' ', str(X.iloc[sen]))
谢谢你,iloc 正在工作。我认为熊猫版本存在一些问题。
太好了,我会发表评论作为答案
【参考方案1】:
将此行上的索引从纯切片更改为iloc
:
document = re.sub(r'\W', ' ', str(X.iloc[sen]))
【讨论】:
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