问题
在这个数据文件中,使用“REGION”列将美国分为四个地区。
创建一个查询,查找属于区域1或区域2的县,其名称以“Washington”开头,并且其popestimate105大于其popestimate104。
此函数应返回一个5x2数据帧,其中列=['STNAME','CTYNAME']和与人口普查数据框相同的索引ID(按索引升序排序)。
代码
def answer_eight():
counties=census_df[census_df['SUMLEV']==50]
regions = counties[(counties[counties['REGION']==1]) | (counties[counties['REGION']==2])]
washingtons = regions[regions[regions['COUNTY']].str.startswith("Washington")]
grew = washingtons[washingtons[washingtons['POPESTIMATE2015']]>washingtons[washingtons['POPESTIMATES2014']]]
return grew[grew['STNAME'],grew['COUNTY']]
outcome = answer_eight()
assert outcome.shape == (5,2)
assert list (outcome.columns)== ['STNAME','CTYNAME']
print(tabulate(outcome, headers=["index"]+list(outcome.columns),tablefmt="orgtbl"))
错误
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
<ipython-input-77-546e58ae1c85> in <module>()
6 return grew[grew['STNAME'],grew['COUNTY']]
7
----> 8 outcome = answer_eight()
9 assert outcome.shape == (5,2)
10 assert list (outcome.columns)== ['STNAME','CTYNAME']
<ipython-input-77-546e58ae1c85> in answer_eight()
1 def answer_eight():
2 counties=census_df[census_df['SUMLEV']==50]
----> 3 regions = counties[(counties[counties['REGION']==1]) | (counties[counties['REGION']==2])]
4 washingtons = regions[regions[regions['COUNTY']].str.startswith("Washington")]
5 grew = washingtons[washingtons[washingtons['POPESTIMATE2015']]>washingtons[washingtons['POPESTIMATES2014']]]
/opt/conda/lib/python3.5/site-packages/pandas/core/frame.py in __getitem__(self, key)
1991 return self._getitem_array(key)
1992 elif isinstance(key, DataFrame):
-> 1993 return self._getitem_frame(key)
1994 elif is_mi_columns:
1995 return self._getitem_multilevel(key)
/opt/conda/lib/python3.5/site-packages/pandas/core/frame.py in _getitem_frame(self, key)
2066 def _getitem_frame(self, key):
2067 if key.values.size and not com.is_bool_dtype(key.values):
-> 2068 raise ValueError('Must pass DataFrame with boolean values only')
2069 return self.where(key)
2070
ValueError: Must pass DataFrame with boolean values only
我一无所知。我哪里做错了?
谢谢
你试图使用不同形状的df来掩盖你的df,这是错误的,另外,你通过条件的方式被错误地使用。将df中的列或序列与标量进行比较以生成布尔掩码时,应仅传递条件,而不是连续使用。
你想要:
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