Count occurrences of certain string in entire pandas dataframe

问题

I have following dataframe in pandas

 C1      C2       C3
 10      a        b
 10      a        b
 ?       c        c
 ?       ?        b
 10      a        b
 10      ?        ?

I want to count the occurrences of ? in all the columns

My desired output is column wise sum of occurrences

回答1:

Use:

m=df.eq('?').sum()
pd.DataFrame([m.values],columns=m.index)

   C1  C2  C3
0   2   2   1

Or better :

df.eq('?').sum().to_frame().T #thanks @user3483203

C1  C2  C3
0   2   2   1

来源：https://stackoverflow.com/questions/54714183/count-occurrences-of-certain-string-in-entire-pandas-dataframe