pandas change value if condition code example
Example 1: pandas lambda if else
df['equal_or_lower_than_4?'] = df['set_of_numbers'].apply(lambda x: 'True' if x <= 4 else 'False')
Example 2: pandas update with condition
import pandas as pd
import numpy as np
df = pd.DataFrame({'value':np.arange(1000000)})
df['value'] = np.where(df['value'] > 20000, 0, df['value'])
df.loc[df['value'] > 20000, 'value'] = 0
df['value'] = df['value'].mask(df['value'] > 20000, 0)
df['a'] = df.where(df.a <= 20000, 0)
Example 3: change pandas column value based on condition
In [41]:
df.loc[df['First Season'] > 1990, 'First Season'] = 1
df
Out[41]:
Team First Season Total Games
0 Dallas Cowboys 1960 894
1 Chicago Bears 1920 1357
2 Green Bay Packers 1921 1339
3 Miami Dolphins 1966 792
4 Baltimore Ravens 1 326
5 San Franciso 49ers 1950 1003