如果第二個元素相同，則將列表中的第一個元素合併爲一個元組？

Question

我有元組的列表：

[('Donald', 'PERSON'), ('Trump', 'PERSON'), ('enters', 'O'), ('the', 'O'), ('White', 'LOCATION'), ('House', 'LOCATION')] 

，我想輸出是：

[('Donald Trump'), ('enters the'), ('White House')] 

下面的代碼讓我更接近想要的結果，但我不是很熟悉groupby功能呢。

mergedTags = [] 
    from itertools import groupby 
    for tag, chunk in groupby(tagList, lambda x: x[1]): 
     if tag != "O": 
      tagMerged = " ".join(w for w, t in chunk) 
      mergedTags.extend([tagMerged]) 
     else: 
      #tagMerged = " ".join(t for t, w in chunk) 
      for word, chunk in groupby(tagList, lambda x: x[0]): 
       mergedTags.extend([word]) 

    print(mergedTags) 

Answer 1

您可以使用itertools.groupby與列表理解表達爲：

from itertools import groupby 
my_list = [('Donald', 'PERSON'), ('Trump', 'PERSON'), ('enters', 'O'), ('the', 'O'), ('White', 'LOCATION'), ('House', 'LOCATION')] 

output_list = [tuple(i[0] for i in e) for _, e in groupby(my_list, lambda x: x[1])] 
#    ^generate the desired tuple 

凡output_list數值保持將是：

[('Donald', 'Trump'), ('enters', 'the'), ('White', 'House')]