在列中查找重复项，返回唯一项并从 python 中的另一列列出其对应的值

Question

我想从第 1 列中删除重复项，并在第 2 列中返回与使用 python 的每个唯一项关联的值的相关列表。

输入是

1 2
Jack London 'Son of the Wolf'
Jack London 'Chris Farrington'
Jack London 'The God of His Fathers'
Jack London 'Children of the Frost'
William Shakespeare  'Venus and Adonis' 
William Shakespeare 'The Rape of Lucrece'
Oscar Wilde 'Ravenna'
Oscar Wilde 'Poems'

而输出应该是

1 2
Jack London 'Son of the Wolf, Chris Farrington, Able Seaman, The God of His Fathers,Children of the Frost'
William Shakespeare 'The Rape of Lucrece,Venus and Adonis' 
Oscar Wilde 'Ravenna,Poems'

其中第二列包含与每个项目关联的值的总和。 我尝试了字典上的 set() 函数

dic={'Jack London': 'Son of the Wolf', 'Jack London': 'Chris Farrington', 'Jack London': 'The God of His Fathers'}
set(dic)

但它只返回字典的第一个键

set(['Jack London'])

Answer 1

在 Python 中，字典的每个键只能包含一个值。但该值可以是项目的集合：

>>> d = {'Jack London': ['Son of the Wolf', 'Chris Farrington']}
>>> d['Jack London']
['Son of the Wolf', 'Chris Farrington']

要从一系列键值对构造这样的字典，您可以执行以下操作：

dct = {}
for author, title in items:
    if author not in dct:
        # Create a new entry for the author
        dct[author] = [title]
    else:
        # Add another item to the existing entry
        dct[author].append(title)

循环体可以像这样更简洁：

dct = {}
for author, title in items:
    dct.setdefault(author, []).append(title)

Answer 2

您应该使用itertools.groupby，因为您的列表已排序。

rows = [('1', '2'),
        ('Jack London', 'Son of the Wolf'),
        ('Jack London', 'Chris Farrington'),
        ('Jack London', 'The God of His Fathers'),
        ('Jack London', 'Children of the Frost'),
        ('William Shakespeare', 'Venus and Adonis'),
        ('William Shakespeare', 'The Rape of Lucrece'),
        ('Oscar Wilde', 'Ravenna'),
        ('Oscar Wilde', 'Poems')]
# I'm not sure how you get here, but that's where you get

from itertools import groupby
from operator import itemgetter

grouped = groupby(rows, itemgetter(0))
result = {group:', '.join([value[1] for value in values]) for group, values in grouped}

这会给你一个结果：

In [1]: pprint(result)
{'1': '2',
 'Jack London': 'Son of the Wolf, Chris Farrington, The God of His Fathers, '
                'Children of the Frost',
 'Oscar Wilde': 'Ravenna, Poems',
 'William Shakespeare': 'Venus and Adonis, The Rape of Lucrece'}