如何使用Python将另一个数据帧映射到另一个数据帧

Question

我有两个Pandas DataFrame。我有一个包含3列兴趣的数据框，其中包含不同产品的客户ID。我有第二个数据框，其中包含客户的姓名。我想扩展第一个数据框，使其具有包含客户名称的新列作为单独的列。例如，我想扩展与第二个数据帧映射的主数据帧，但要使用新的列，如customer_1_name, customer_2_name, customer_3_name

请记住，一个客户可以有不同的客户ID包

为了支持我的问题。我附上了两个数据帧的一个片段

# DataFrame 1
dFrame_main = ({'Pageviews': [22.0,
  22.0,
  21.0,
  20.0,
  18.0,
  15.0,
  14.0,
  14.0,
  13.0,
  13.0,
  12.0,
  12.0,
  12.0,
  12.0,
  12.0,
  12.0,
  12.0,
  12.0,
  11.0,
  11.0],
 'Unique Pageviews': [8.0,
  8.0,
  16.0,
  14.0,
  14.0,
  12.0,
  13.0,
  12.0,
  13.0,
  13.0,
  8.0,
  8.0,
  5.0,
  11.0,
  12.0,
  7.0,
  9.0,
  9.0,
  5.0,
  5.0],
 'Avg. Time on Page': ['0:00:23',
  '0:00:23',
  '0:03:49',
  '0:00:31',
  '0:00:21',
  '0:00:27',
  '0:00:38',
  '0:00:15',
  '0:01:24',
  '0:00:20',
  '0:00:13',
  '0:00:13',
  '0:02:14',
  '0:00:33',
  '0:00:46',
  '0:00:14',
  '0:01:08',
  '0:01:08',
  '0:01:51',
  '0:01:51'],
 'CustomerID_1': ['465',
  '465',
  '162',
  '124',
  '920',
  '920',
  '920',
  '920',
  '920',
  '920',
  '165',
  '165',
  '166',
  '920',
  '920',
  '920',
  '162',
  '162',
  '1846',
  '118'],
 'CustomerID_2': ['702',
  '702',
  '446',
  '125',
  '470',
  '470',
  '470',
  '470',
  '470',
  '212',
  '1920',
  '1920',
  '868',
  '470',
  '470',
  '470',
  '873',
  '873',
  '862',
  '862'],
 'CustomerID_3': ['167',
  '167',
  '570',
  np.nan,
  '212',
  '212',
  '212',
  '212',
  '212',
  np.nan,
  '1670',
  '1670',
  '274',
  '212',
  '212',
  '212',
  '764',
  '764',
  '584',
  '584']})

# DataFrame 2
dFrame = pd.DataFrame({'CustomerID': [569,
  923,
  162,
  1798,
  920,
  470,
  1943,
  1798,
  162,
  124,
  1053,
  212,
  923,
  1747,
  1921,
  166,
  165,
  465,
  862,
  584],
 'CustomerNames': ['Thomas Bills',
  'Demi Boras',
  'Jerry wills',
  'Pills Wilson',
  'Jerry wills',
  'Harsh wilson',
  'Alli Pees',
  'Pills Wilson',
  'Jerry wills',
  'Pills Wilson',
  'Fedolls Feba',
  'Pills Wilson',
  'Demi Boras',
  'Harsh wilson',
  'Matt Lills',
  'Pills Wilson',
  'Twist Tells',
  'Jerry wills',
  'Matt Lills',
  'Balls tails']})

请注意：这只是大型数据帧的一个片段，您可以理解我试图解决的问题

我曾尝试过这样做，不幸的是，这无助于我的处境

谢谢你的时间

Answer 1

# Build a mapper series. For this to work we need to ensure that 
# - the datatypes are the same (string)
# - that we have no repeated values

mapper = dFrame.astype(str).drop_duplicates().set_index('CustomerID')['CustomerNames']

# Apply the mapping (the value of the column will be looked up in the index of the `mapper` series)
dFrame_main['CustomerID_1_name'] = dFrame_main['CustomerID_1'].map(mapper)
dFrame_main['CustomerID_2_name'] = dFrame_main['CustomerID_2'].map(mapper)
dFrame_main['CustomerID_3_name'] = dFrame_main['CustomerID_3'].map(mapper)