pandas.core.base.DataError：没有要聚合的数字类型

Question

对Pandas数据透视表功能不熟悉。 我遵循本指南[1]。 修改现有的excel文件并尝试创建表输出。

im试图像这样索引数据透视表；

def generate_invoice_summary_info():                                                           
    file_path = 'output.xlsx'                                                                  
    df = pd.read_excel(file_path, sheet_name='Invoice Details', usecols="E:G,I,L:N")                                                                                                          
    df["Invoice Cost Centre"] = df["Invoice Cost Centre"].astype("category")                   
    df["Invoice Cost Centre"].cat.set_categories(["RIM", "R3TM", "D3TM", "R5M"], inplace=True) 

    df['Price'] = df['Price'].astype(str)                                                      
    df['Period From'] = df['Period From'].astype(str)                                          

    pd.pivot_table(df, index=["Invoice Cost Centre", "Invoice Category"])  

出现以下错误

pandas.core.base.DataError: No numeric types to aggregate  

为什么会出现此错误？ 我正在尝试根据“发票费用中心”，“发票类别”列汇总表格

[1] https://pbpython.com/pandas-pivot-table-explained.html