尝试在 Pandas Dataframe 上运行函数时出现 TypeError

Posted 2023-03-16

【中文标题】尝试在 Pandas Dataframe 上运行函数时出现 TypeError

【英文标题】：TypeError when trying to run function on Pandas Dataframe

【发布时间】：2021-10-14 16:56:04

【问题描述】：

我有一个名为 month_values 的 pandas 数据框，其值如下：

Area	Thrpt_A	Thrpt_B	Thrpt_C	Thrpt_D
Galle	9581.539079	6790.664649	8340.489900	5940.886763
Colombo	5948.006563	4245.619220	7084.931812	3915.933362

数据类型是

Area             object
Thrpt_A          float64
Thrpt_B          float64
Thrpt_C          float64
Thrpt_D          float64

我已经定义了一个带有嵌套 if-else 的函数以应用于此数据帧，如下所示：

def mark_func(df):
    if (df['Area'] == "Colombo"):
        if (df['Thrpt_A'] >= 8000):
            return 'A'
        elif (df['Thrpt_A'] < (8000)):
            if (df['Thrpt_A'] >= df['Thrpt_B']) and (['Thrpt_A'] >= df['Thrpt_C']) and (['Thrpt_A'] >= df['Thrpt_D']):
                return 'A'
            elif (df['Thrpt_B'] >= df['Thrpt_C']) and (df['Thrpt_B'] >= df['Thrpt_D']):
                return 'B'
            elif (df['Thrpt_C'] >= df['Thrpt_B']) and (df['Thrpt_C'] >= df['Thrpt_D']):
                return 'C'
            elif (df['Thrpt_D'] >= df['Thrpt_B']) and (df['Thrpt_D'] >= df['Thrpt_C']):
                return 'D'
    else:
        if (df['Thrpt_A'] >= 4000):
            return 'A'
        elif (df['Thrpt_A'] < (4000)):
            if (df['Thrpt_A'] >= df['Thrpt_B']) and (['Thrpt_A'] >= df['Thrpt_C']) and (['Thrpt_A'] >= df['Thrpt_D']):
                return 'A'
            elif (df['Thrpt_B'] >= df['Thrpt_C']) and (df['Thrpt_B'] >= df['Thrpt_D']):
                return 'B'
            elif (df['Thrpt_C'] >= df['Thrpt_B']) and (df['Thrpt_C'] >= df['Thrpt_D']):
                return 'C'
            elif (df['Thrpt_D'] >= df['Thrpt_B']) and (df['Thrpt_D'] >= df['Thrpt_C']):
                return 'D'

我期待的输出如下：

Area	Thrpt_A	Thrpt_B	Thrpt_C	Thrpt_D	Mark
Galle	9581.539079	6790.664649	8340.489900	5940.886763	A
Colombo	5948.006563	4245.619220	7084.931812	3915.933362	C

但是，当我使用以下代码行应用该函数时：

month_values['Mark'] = month_values.apply(mark_func, axis=1)

我收到以下错误：

TypeError: ("'>=' not supported between instances of 'list' and 'float'", 'occurred at index 279')

我不确定我在这里做错了什么。如有任何解决问题的建议，将不胜感激。

【参考方案1】：

这部分代码：

... and (['Thrpt_A'] >= df['Thrpt_C']) and (['Thrpt_A'] >= df['Thrpt_D']):

应该是：

... and (df['Thrpt_A'] >= df['Thrpt_C']) and (df['Thrpt_A'] >= df['Thrpt_D']):

注意df