CODEWITHSUNDEEP
pythonpandasnanmultiplication
rakamakafo
rakamakafo

Reputation: 159

How to multiply two columns in pandas, by only non-NaN values?

I am curious if it is possible to multiply two columns A,B by only non NAN values.

I have the following dataframe with the expected results: 

                         A     B     C
    Date     Symbol  

  1/1/2017    BTC       Nan    2     Nan
              ETH        3     Nan   6
              XRP        2     Nan   4
  1/2/2017    BTC       Nan    3     Nan
              ETH        1     Nan    3
              XRP        2     Nan    6

I am trying to multiply non Nan values of column A by non-NaN values of Column B and assign the result to column C. I want to iterate over the dataframe. I have tried few things, but nothing is working.

Upvotes: 2

Views: 5022

Answers (2)

Wanderson Bittencourt
Wanderson Bittencourt

Reputation: 1

df = pd.DataFrame(data=obj)
df['t'] = (df['col1'].ffill())* (df['col2'].ffill())```

   col1  col2    t
0   1.0   3.0  3.0
1   2.0   4.0  8.0
2   1.0   NaN  4.0
3   NaN   8.0  8.0

Upvotes: 0

BENY
BENY

Reputation: 323286

Check with ffill

#df=df.replace('Nan',np.nan)# Nan is not NaN , replace it 
#df=df.apply(pd.to_numeric,1) # convert to numeric 
df.C=df.A*(df.B.ffill())
df
Out[130]: 
                   A    B    C
Date     Symbol               
1/1/2017 BTC     NaN  2.0  NaN
         ETH     3.0  NaN  6.0
         XRP     2.0  NaN  4.0
1/2/2017 BTC     NaN  3.0  NaN
         ETH     1.0  NaN  3.0
         XRP     2.0  NaN  6.0

Upvotes: 4

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