将替换字符串替换为键并将替换字符串替换为值。蟒蛇

Question

我有一个字典字符串被替换为为keys及其替换作为值。除了用标记来查看字符串标记外，还有更好/更快的替换方法吗？

我已经做了这样：

segmenter = {'foobar':'foo bar', 'withoutspace':'without space', 'barbar': 'bar bar'} 

sentence = "this is a foobar in a barbar withoutspace" 

for i in sentence.split(): 
    if i in segmenter: 
    sentence.replace(i, segmenter[i]) 

Answer 1

字符串在Python是不可改变的。所以，str.replace返回一个新的字符串，而不是修改原始字符串。您可以使用str.join()和列表理解这里：

>>> segmenter = {'foobar':'foo bar', 'withoutspace':'without space', 'barbar': 'bar bar'} 
>>> sentence = "this is a foobar in a barbar withoutspace" 

>>> " ".join([ segmenter.get(word,word) for word in sentence.split()]) 
'this is a foo bar in a bar bar without space' 

与str.replace的另一个问题是，它也将与

"abar barb"更换的话就像"abarbarb"。

Answer 2

re.sub可以调用返回的替代

segmenter = {'foobar':'foo bar', 'withoutspace':'without space', 'barbar': 'bar bar'} 
sentence = "this is a foobar in a barbar withoutspace" 

import re 

def fn(match): 
    return segmenter[match.group()] 

print re.sub('|'.join(re.escape(k) for k in segmenter), fn, sentence)