获取SettingWithCopyWarning：使用.replace和.drop

Question

我正在尝试格式化我的两个数据框，并开始获得SettingWithCopyWarnings。我知道它警告我，我可能正在使用副本，但我不知道如何解决这个问题，因为我还是Pandas的新手。

这是我的代码：

Bought = df2[df2['Quantity'] > 0] 
Sold = df2[df2['Quantity'] < 0] 
Bought.drop('Unit', axis = 1, inplace = True) 
Sold.drop('Unit', axis = 1, inplace = True) 
Bought['Account'].replace(to_replace = 'F1105', value = 'On', inplace = True) 
Bought['Account'].replace(to_replace = 'F1121', value = 'Off', inplace = True) 
Sold['Account'].replace(to_replace = 'F1105', value = 'On', inplace = True) 
Sold['Account'].replace(to_replace = 'F1121', value = 'Off', inplace = True)
Bought.reset_index(drop = True, inplace = True)
Sold.reset_index(drop = True, inplace = True)

感谢您的帮助。

Answer 1

Bought和Sold是DataFrame的切片;要摆脱警告，请先：

Bought = df2[df2['Quantity'] > 0].copy() 
Sold = df2[df2['Quantity'] < 0].copy()