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
df.loc[df['First Season'] > 1990, 'First Season'] = 1
df.loc[df['employrate'] > 70, 'employrate'] = 7
df['New Column'] = np.where(df['A']==0, df['B'], df['A'])
df['column'].mask(df['column'] == 'original_value', new_value, inplace=True)
d.loc[d["conditionDisplayName"] == "Brand New", "conditionDisplayName"] = 6
d.loc[d["conditionDisplayName"] != "Brand New", "conditionDisplayName"] = 4