Fill missing values in Pandas
The “fillna” function in Pandas not only can replace missing values with a given constant value, like in this example:
1 2 3 4 import pandas as pd import numpy as np df = pd.DataFrame([[np.nan], , [np.nan], ]) df
You can also replace a missing value with the next (or previous) value in the data frame!
1 df.fillna(method = "ffill")
Note that the first value cannot be replaced because nothing is preceding it.
You can also use the value of the next row to fill a missing value.
1 df.fillna(method = "bfill")
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