How to check for Boolean condition in pandas dataframe

问题

I have Alcohol_df dataframe in which qualification is a column.

I have created a list as follows:

Graduate_list=['B.tech','b.tech','b-tech','Btech','BE',
               'B.E', 'b.e','BACHELOR','bachelor','BSc',
               'Bsc','bsc','BSC','BBM']

I did

Alcohol_df['qualification'].isin(Graduate_list)

to find which columns contains the elements from the list.

I want to do some operation on the dataframe if its value is in the list.I did

if ((Alcohol_df['qualification'].isin(Graduate_list)):

But getting this error

ValueError: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().

Kindly help me solve this

回答1:

I think you need any (return True if at least one value is True) or all (return True if all values are Trues) for return scalar, because else it return boolean Series:

if (Alcohol_df['qualification'].isin(Graduate_list).any()):

Sample:

Alcohol_df = pd.DataFrame({'qualification':['B.tech','a','Btech'],
                           'B':[4,5,6]})

print (Alcohol_df)
   B qualification
0  4        B.tech
1  5             a
2  6         Btech

print (Alcohol_df['qualification'].isin(Graduate_list))
0     True
1    False
2     True
Name: qualification, dtype: bool

if (Alcohol_df['qualification'].isin(Graduate_list).any()):
    print ('bingo')

If need select DataFrame by boolean Series use boolean indexing:

df1 = Alcohol_df[Alcohol_df['qualification'].isin(Graduate_list)]
print (df1)
   B qualification
0  4        B.tech
2  6         Btech

来源：https://stackoverflow.com/questions/43582154/how-to-check-for-boolean-condition-in-pandas-dataframe

标签

python

pandas