使用 pandas 连接数据
Aaren Stubberfield
Instructor
可能的合并问题：
可能的拼接问题：
.merge(validate=None)：
.merge(validate=None)
'one_to_one'
'one_to_many'
'many_to_one'
'many_to_many'
表名：tracks
tracks
tid name aid mtid gid u_price 0 2 Balls to the... 2 2 1 0.99 1 3 Fast As a Shark 3 2 1 0.99 2 4 Restless and... 3 2 1 0.99
表名：specs
specs
tid milliseconds bytes 0 2 342562 5510424 1 3 230619 3990994 2 2 252051 4331779
tracks.merge(specs, on='tid', validate='one_to_one')
Traceback (most recent call last): MergeError: Merge keys are not unique in right dataset; not a one-to-one merge
albums.merge(tracks, on='aid', validate='one_to_many')
aid title artid tid name mtid gid u_price 0 2 Balls to the... 2 2 Balls to the... 2 1 0.99 1 3 Restless and... 2 3 Fast As a Shark 2 1 0.99 2 3 Restless and... 2 4 Restless and... 2 1 0.99
.concat(verify_integrity=False)：
.concat(verify_integrity=False)
False
表名：inv_feb
inv_feb
cid invoice_date total iid 7 38 2009-02-01 1.98 8 40 2009-02-01 1.98 9 42 2009-02-02 3.96
表名：inv_mar
inv_mar
cid invoice_date total iid 9 17 2009-03-04 1.98 15 19 2009-03-04 1.98 16 21 2009-03-05 3.96
pd.concat([inv_feb, inv_mar], verify_integrity=True)
Traceback (most recent call last): ValueError: Indexes have overlapping values: Int64Index([9], dtype='int64', name='iid')
pd.concat([inv_feb, inv_mar], verify_integrity=False)
cid invoice_date total iid 7 38 2009-02-01 1.98 8 40 2009-02-01 1.98 9 42 2009-02-02 3.96 9 17 2009-03-04 1.98 15 19 2009-03-04 1.98 16 21 2009-03-05 3.96
原因：
应对：
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