Method for filling missing data in Fillna of Pandas

Agreement:


import pandas as pd
import numpy as np
from numpy import nan as NaN

Fill in missing data

fillna () is the main treatment.


df1=pd.DataFrame([[1,2,3],[NaN,NaN,2],[NaN,NaN,NaN],[8,8,NaN]])
df1

Code result:

To fill with constants:


df1.fillna(100)

Code result:

Fill in different constants through dictionaries:


df1.fillna({0:10,1:20,2:30})

Code result:

Pass in inplace=True to directly modify the original object:


df1.fillna(0,inplace=True)
df1

Code result:

Pass in method= "" to change the interpolation mode:


df2=pd.DataFrame(np.random.randint(0,10,(5,5)))
df2.iloc[1:4,3]=NaN;df2.iloc[2:4,4]=NaN
df2

Code result:


df2.fillna(method='ffill')# Fill with the previous value

Code result:

Passing in limit= "" Limit the number of padding:


df2.fillna(method='bfill',limit=2)

Code result:

Pass in axis= "" to modify the fill direction:


df2.fillna(method="ffill",limit=1,axis=1)

Code result: