使用 pandas 一起添加列表元素 [英] Using pandas to add list elements together

问题描述

我有以下几则字典:

items = [ 
{
    'FirstName': 'David',
    'Language': ['en',]
},
{
    'FirstName': 'David',
    'Language': ['fr',]
},

{
    'FirstName': 'David',
    'Language': ['en',]
},
{
    'FirstName': 'Bob',
    'Language': ['en',]
}
]

我想按名字分组，并将唯一的语言添加到一起，就像这样:

Which I want to group by on FirstName and add the unique languages together, like so:

items = [ 
{
    'FirstName': 'David',
    'Language': ['en', 'fr']
},

{
    'FirstName': 'Bob',
    'Language': ['en',]
}
]

我将使用的SQL是:

SELECT FirstName, GROUP_CONCAT(DISTINCT Language ORDER BY Language)
FROM items
GROUP BY FirstName

使用大熊猫，我如何将其结合起来并在FirstName上进行分组并获得一系列独特的语言?这是我到目前为止的内容:

Using pandas, how would I combine this and do a group by on FirstName and get an array of unique languages? Here is what I have so far:

>>> df = pandas.DataFrame(items)
>>> df.groupby('FirstName')['Language']
      .apply(lambda x: list(set(x))) # this line is off
      .reset_index()
      .to_dict(orient='records')

推荐答案

将所有内容与总和，transform值进行设置，然后to_dict()

Aggregate all with sum, transform values to set and then to_dict()

>>> df.groupby('FirstName').sum()["Language"].transform(set).reset_index().to_dict(orient='records')

[{'FirstName': 'Bob', 'Language': {'en'}},
 {'FirstName': 'David', 'Language': {'en', 'fr'}}]

这篇关于使用 pandas 一起添加列表元素的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！