SettingWithCopyWarning Pandas 根据条件在列中设置值

Question

我目前的代码如下：

            conditions = [
                (df1['item-condition'] == '1'),
                (df1['item-condition'] == '2'),
                (df1['item-condition'] == '3'),
                (df1['item-condition'] == '4')
            ]
            choices = ['Used - Like New', 'Used - Very Good', 'Used - Good', 'Used - Acceptable']
            df1['item-condition'] = np.select(conditions, choices)

我正在尝试将“项目条件”列中的值从 1 设置为像新的，从 2 设置为非常好等
但是使用此代码我收到错误： SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame. Try using.loc[row_indexer,col_indexer] = value instead SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame. Try using.loc[row_indexer,col_indexer] = value instead
我的代码到底错在哪里，是否可以重写它以不引发此警告？

编辑以显示示例数据：

    item-condition
0   2
1   2
2   3
3   1

应改为：

    item-condition
0   Used - Very Good
1   Used - Very Good
2   Used - Good
3   Used - Like New

Answer 1

将其转换为 numpy 并重新附加它

a = df1['item-condition'].to_numpy()
cond_list = [a=1,a=2,a=3,a=4]
df1['item-condition'] = np.select(cond_list,choices,'potato')