Python Correlation index-CodePudding

Given a data frame "df", I need to obtain the correlation index between mean price and total volume for Region = "California".

Given Dataframe:

Correlation index between California mean price and total volume:

cali_mean = df.groupby('Region').get_group('California')['AveragePrice'].mean()
max_volume = (df.groupby('Region')['TotalVolume'].sum()).max() #Output: 1028981653.17

# Correlation index between California mean price and total volume
df[cali_mean].corr(df['max_volume'])

When I tried determining the correlation index between California's mean price and total volume, I got the following error message. Is there a way to fix this?

Error message

KeyError                                  Traceback (most recent call last)
~/opt/miniconda3/lib/python3.9/site-packages/pandas/core/indexes/base.py in get_loc(self, key, method, tolerance)
   3620             try:
-> 3621                 return self._engine.get_loc(casted_key)
   3622             except KeyError as err:

~/opt/miniconda3/lib/python3.9/site-packages/pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()

~/opt/miniconda3/lib/python3.9/site-packages/pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

KeyError: 1.3939644970414187

The above exception was the direct cause of the following exception:

KeyError                                  Traceback (most recent call last)
/var/folders/wv/42dn23fd1cb0czpvqdnb6zw00000gn/T/ipykernel_18660/3247367876.py in <module>
      1 # Correlation index between California mean price and total volume
----> 2 df[cali_mean].corr(df['max_volume'])

~/opt/miniconda3/lib/python3.9/site-packages/pandas/core/frame.py in __getitem__(self, key)
   3503             if self.columns.nlevels > 1:
   3504                 return self._getitem_multilevel(key)
-> 3505             indexer = self.columns.get_loc(key)
   3506             if is_integer(indexer):
   3507                 indexer = [indexer]

~/opt/miniconda3/lib/python3.9/site-packages/pandas/core/indexes/base.py in get_loc(self, key, method, tolerance)
   3621                 return self._engine.get_loc(casted_key)
   3622             except KeyError as err:
-> 3623                 raise KeyError(key) from err
   3624             except TypeError:
   3625                 # If we have a listlike key, _check_indexing_error will raise

KeyError: 1.3939644970414187

CodePudding user response：

Note that the correlation is a measure of two vectors. So you can use:

df = pd.read_csv('avocado.csv')
temp = df[df['Region']=='California']
temp['AveragePrice'].corr(temp['TotalVolume'])

Output:

-0.7913852550045145