Question

我试图从字符串列表中的每个元素中删除子字符串。我无法弄清楚如何处理具有多个我想删除的子串（停用词）的字符串的情况。

wines = ("2008 Chardonnay", "Cabernet Sauvignon 2009", "Bordeaux 2005 Cotes du Rhone")
stop_words = ("2005", "2008", "2009", "Cotes du Rhone")
result = []

for wine in wines:
    for stop in stop_words:
        if stop in wine:
            x = wine.replace(stop, "")
            result.append(x)

print result

将if语句更改为for或while会返回垃圾或挂起。有什么建议吗？

Answer 1

稍微缩进并改变变量可以解决您的问题

for wine in wines:
    glass=wine #Lets pour your wine in a glass
    for stop in stop_words:
        if stop in glass: #Is stop in your glass? 
            #Replace stop in glass and pour it in the glass again
            glass = glass.replace(stop, "") 
    result.append(glass) #Finally pour the content from your glass to result


result
[' Chardonnay', 'Cabernet Sauvignon ', 'Bordeaux  ']

如果您想冒险，可以使用正则表达式。我相信在这种情况下，正则表达式可能比简单循环更快

>>> for wine in wines:
    result.append(re.sub('('+'|'.join(stop_words)+')','',wine))    

>>> result
[' Chardonnay', 'Cabernet Sauvignon ', 'Bordeaux  ']
>>>

或者将其作为列表理解

>>> [re.sub('('+'|'.join(stop_words)+')','',wine) for wine in wines]
[' Chardonnay', 'Cabernet Sauvignon ', 'Bordeaux  ']
>>>

Answer 2

wines = ("2008 Chardonnay", "Cabernet Sauvignon 2009", "Bordeaux 2005 Cotes du Rhone")
stop_words = ("2005", "2008", "2009", "Cotes du Rhone")
result = []

for wine in wines:
    x = wine
    for stop in stop_words:        
        x = x.replace(stop, "")
    result.append(x)

print result

使用regex会更好IMO

>>> wines = ("2008 Chardonnay", "Cabernet Sauvignon 2009", "Bordeaux 2005 Cotes du Rhone")
>>> stop_words = ("2005", "2008", "2009", "Cotes du Rhone")
>>> import re
>>> [re.sub('|'.join(stop_words),'',wine) for wine in wines]
[' Chardonnay', 'Cabernet Sauvignon ', 'Bordeaux  ']

Answer 3

作为一个单行，考虑到jamylaks建议使用strip()：

[reduce(lambda x,y: x.replace(y, "").strip(), stop_words, wine) for wine in wines]

请注意，这在Python 2.x中运行良好，但在Python 3中运行不正常，因为reduce()已移至单独的库中。如果您使用的是Python 3，请执行以下操作：

import functools as ft
[ft.reduce(lambda x,y: x.replace(y, "").strip(), stop_words, wine) for wine in wines]

使用Python的replace（）方法实现停用词功能

3 个答案: