pandas replace nan with value from another column code example

Example 1: replace nan in pandas

df['DataFrame Column'] = df['DataFrame Column'].fillna(0)

Example 2: pandas replace null values with values from another column

#Python
#Col 1 = where you want the values replaced
#Col 2 = where you want to take the values from
df.["Col 1"].fillna(df.["Col 2"], inplace=True)

Example 3: replace all nan values in dataframe

# Replacing all nan values with 0 in Dataframe
df = df.fillna(0)

Example 4: pandas if nan, then the row above

df.fillna(method='ffill')