正則表達式用Python中的負面展望替換

Question

我試圖刪除圍繞普通文本的單引號。例如，給出的列表：

alist = ["'ABC'", '(-inf-0.5]', '(4800-20800]', "'\\'(4.5-inf)\\''", "'\\'(2.75-3.25]\\''"] 

我想談談 「 'ABC'」 到 「ABC」，但保留其他的報價，那就是：

alist = ["ABC", '(-inf-0.5]', '(4800-20800]', "'\\'(4.5-inf)\\''", "'\\'(2.75-3.25]\\''"] 

我試圖用look-如下文頭：

fixRepeatedQuotes = lambda text: re.sub(r'(?<!\\\'?)\'(?!\\)', r'', text) 
print [fixRepeatedQuotes(str) for str in alist] 

但收到錯誤消息：

sre_constants.error: look-behind requires fixed-width pattern. 

任何其他解決方法？提前感謝！

Answer 1

嘗試應該工作：

result = re.sub("""(?s)(?:')([^'"]+)(?:')""", r"\1", subject) 

解釋

""" 
(?:   # Match the regular expression below 
    '   # Match the character 「'」 literally 
) 
(   # Match the regular expression below and capture its match into backreference number 1 
    [^'"]  # Match a single character NOT present in the list 「'"」 
     +   # Between one and unlimited times, as many times as possible, giving back as needed (greedy) 
) 
(?:   # Match the regular expression below 
    '   # Match the character 「'」 literally 
) 
""" 

Answer 2

re.sub接受一個函數作爲替換文本。因此，

re.sub(r"'([A-Za-z]+)'", lambda match: match.group(), "'ABC'") 

產生

"ABC"