在Python中使用正则表达式将一个字符串替换为另一个字符串: Error: re.error: bad转义\w位置0

Question

我正在尝试用'word_one‘替换出现的内容，例如'word one’。将空格替换为“_”。

下面是我的代码：

labels_ls = ['word <= 0.01', 'word_two <= 0.23', 'word three <= 0.01']

regex_whitespace = r'\w+\s+\w+\b'
new_regex = r'\w+\_+\w+\b'
pattern = re.compile(regex_whitespace) # this I just added after reviewing other related questions

# Loop through labels_ls to find any ngrams whitespace separated labels (i.e gilt maximal)

for i in labels_ls:
    if re.match(regex_whitespace, i):
        # replace the whitespace with a '_' to form gilt*maximal
        new_string = re.sub(pattern, new_regex, i)
        print('new string: ', new_string)

我已经在这里测试了我的正则表达式https://pythex.org，它按要求工作，但是当我运行这段代码时，我得到了以下错误：

re.error:位置0处的错误转义\w

我已经看过了所有相关的回答问题：

how to fix - error: bad escape \u at position 0

和

Regex: Replace one pattern with another

我已经尝试删除上面问题中提到的regex之前的r，但是仍然不起作用。

我也尝试过使用compile()，但也没有解决这个问题

labels_ls = ['internal_punctuation <= 0.042', 'darf <= 0.717', 'formal_global_yes <= 0.5', 'wert <= 0.272', 'signal <= 0.5', 'Flesch_Index <= 0.813', 'zulass <= 0.379', 'polarity <= 0.713', 'Nb_of_auxiliary <= 0.071', 'gini = 0.0', 'polarity <= 0.375', 'gini = 0.0', 'Nb_of_verbs <= 0.094', 'weakwords_nb <= 0.143', 'passive_global_yes <= 0.5', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'Nb_of_verbs <= 0.094', 'passive_global_yes <= 0.5', 'WPS <= 0.062', 'measurement_values_no <= 0.5', 'gini = 0.0', 'SPW <= 0.575', 'weird_words <= 0.042', 'weakwords_nb <= 0.036', 'SPW <= 0.272', 'gini = 0.0', 'words_nb <= 0.033', 'gini = 0.5', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'Flesch_Index <= 0.774', 'SPW <= 0.331', 'gini = 0.0', 'gini = 0.0', 'Comp_conj <= 0.375', 'SPW <= 0.111', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'Sub_Conj <= 0.25', 'weird_words <= 0.208', 'zsdf <= 0.5', 'signal <= 0.297', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'words_nb <= 0.164', 'Aux_Start_no <= 0.5', 'gini = 0.0', 'Nb_of_Umsetzbarkeit_conj <= 0.167', 'werden <= 0.125', 'darf <= 0.297', 'polarity <= 0.925', 'SPW <= 0.376', 'WPS <= 0.11', 'numerical_values <= 0.091', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'WPS <= 0.11', 'gini = 0.0', 'gini = 0.0', 'polarity <= 0.25', 'gini = 0.0', 'Flesch_Index <= 0.663', 'words_nb <= 0.033', 'SPW <= 0.475', 'gini = 0.0', 'gini = 0.0', 'Comp_conj <= 0.125', 'gini = 0.56', 'gini = 0.0', 'Flesch_Index <= 0.75', 'gini = 0.444', 'gini = 0.0', 'Aux_Start_yes <= 0.5', 'darf <= 0.241', 'Nb_of_verbs <= 0.156', 'gini = 0.0', 'SPW <= 0.246', 'polarity <= 0.675', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'Sub_Conj <= 0.25', 'numerical_values <= 0.227', 'funktion <= 0.348', 'internal_punctuation <= 0.458', 'polarity <= 0.375', 'gini = 0.0', 'Nb_of_verbs <= 0.031', 'gini = 0.0', 'Flesch_Index <= 0.409', 'gini = 0.0', 'numerical_values <= 0.136', 'WPS <= 0.065', 'darf <= 0.359', 'Nb_of_Umsetzbarkeit_conj <= 0.167', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'formal_global_no <= 0.5', 'WPS <= 0.164', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'gini = 0.0', 'gilt randbeding <= 0.181', 'fahrzeug <= 0.352', 'gini = 0.0', 'zulass <= 0.082', 'gini = 0.0', 'gini = 0.0', 'fur <= 0.194', 'weakwords_nb <= 0.321', 'gini = 0.444', 'gini = 0.0', 'gini = 0.0', 'Nb_of_Umsetzbarkeit_conj <= 0.167', 'Nb_of_verbs <= 0.344', 'gini = 0.0', 'gini = 0.0', 'words_nb <= 0.178', 'gini = 0.0', 'words_nb <= 0.224', 'gini = 0.0', 'gini = 0.0']

Answer 1

您需要使用

regex_whitespace = r'(\w+)\s+(\w+)\b'

然后：

new_string = re.sub(pattern, r'\1_\2', i)

请参阅Python demo online。

关键是，您需要将与第一个正则表达式匹配的单词chars捕获到capturing groups中，然后对匹配的组值使用backreferences。new_regex = r'\w+\_+\w+\b'是多余的，因为您不能使用正则模式作为替换，替换模式只能包含反向引用和转义序列(文字反斜杠必须在那里转义)。