ValueError: Must pass DataFrame with boolean values only

Question

问题

在此数据文件中，美国使用 "REGION" 列分为四个区域。

创建查询以查找属于区域 1 或 2、名称以 'Washington' 开头且 POPESTIMATE2015 大于其 POPESTIMATE 2014 的县。

此函数应该 return 一个 5x2 DataFrame，其列 = ['STNAME'、'CTYNAME'] 并且索引 ID 与 census_df 相同（按索引升序排列）。

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。我哪里错了？

谢谢

Answer 1

您正在尝试使用不同形状的 df 来掩盖您的 df，这是错误的，此外，您传递条件的方式使用不正确。当您将 df 中的列或系列与标量进行比较以生成布尔掩码时，您应该只传递条件，而不是连续使用它。

def answer_eight():
    counties=census_df[census_df['SUMLEV']==50]
    # this is wrong you're passing the df here multiple times
    regions = counties[(counties[counties['REGION']==1]) | (counties[counties['REGION']==2])]
    # here you're doing it again
    washingtons = regions[regions[regions['COUNTY']].str.startswith("Washington")]
    # here you're doing here again also
    grew = washingtons[washingtons[washingtons['POPESTIMATE2015']]>washingtons[washingtons['POPESTIMATES2014']]]
    return grew[grew['STNAME'],grew['COUNTY']]

你想要：

def answer_eight():
    counties=census_df[census_df['SUMLEV']==50]
    regions = counties[(counties['REGION']==1]) | (counties['REGION']==2])]
    washingtons = regions[regions['COUNTY'].str.startswith("Washington")]
    grew = washingtons[washingtons['POPESTIMATE2015']>washingtons['POPESTIMATES2014']]
    return grew[['STNAME','COUNTY']]

Answer 2

def answer_eight():
    df=census_df[census_df['SUMLEV']==50]
    #df=census_df
    df=df[(df['REGION']==1) | (df['REGION']==2)]
    df=df[df['CTYNAME'].str.startswith('Washington')]
    df=df[df['POPESTIMATE2015'] > df['POPESTIMATE2014']]
    df=df[['STNAME','CTYNAME']]
    print(df.shape)
    return df.head(5)

Answer 3


def answer_eight():
    county = census_df[census_df['SUMLEV']==50]
    req_col = ['STNAME','CTYNAME']

    region = county[(county['REGION']<3) & (county['POPESTIMATE2015']>county['POPESTIMATE2014']) & (county['CTYNAME'].str.startswith('Washington'))]
    region = region[req_col]

    return region
answer_eight()

Answer 4

def answer_eight():
    df=census_df
    region1=df[ df['REGION']==1 ]
    region2=df[ df['REGION']==2 ]

    yes_1=region1[ region1['POPESTIMATE2015'] > region1['POPESTIMATE2014']]
    yes_2=region2[ region2['POPESTIMATE2015'] > region2['POPESTIMATE2014']]

    yes_1=yes_1[ yes_1['CTYNAME']=='Washington County' ]
    yes_2=yes_2[ yes_2['CTYNAME']=='Washington County' ]

    ans=yes_1[ ['STNAME','CTYNAME'] ]  
    ans=ans.append(yes_2[ ['STNAME','CTYNAME'] ])
    return ans.sort()

Answer 5

我在Coursera上的问题就是这样解决的

def answer_eight():
    df8 = census_df.copy()
    washington = df8['CTYNAME'].str[0:10] == 'Washington'
    popincrease = df8['POPESTIMATE2015']) > (df8['POPESTIMATE2014']
    region = (df8['REGION'] == 1) | (df8['REGION'] == 2)
    
df8 = df8[region & popincrease & washington]

    return df8[{'STNAME','CTYNAME'}]

answer_eight()

我当时是Pandas的新手，玩了差不多20个LOL

Answer 6

我是这样解决的（我没有在一行中使用任何直接访问census_df的局部变量）解决方案和你看到的其他解决方案差不多，但是在其他解决方案中，他们使用了我的解决方案中的局部变量我没有使用它。

def answer_eight(): 
    return census_df[
          (census_df['SUMLEV'] == 50)                                     &
          ((census_df["REGION"] == 1) | (census_df["REGION"] == 2))       &
          (census_df["CTYNAME"].str.lower()).str.startswith('washington') &
          (census_df["POPESTIMATE2015"] > census_df["POPESTIMATE2014"])        
         ][["STNAME","CTYNAME"]]

ValueError: Must pass DataFrame with boolean values only

ValueError: Must pass DataFrame with boolean values only

python

database

pandas

data-science