python - ValueError : Length mismatch: Expected axis has 2 elements, new values have 3 elements

Question

这是我计划用于创建饼图的代码。

import csv
with open('C:\\Users\Bhuwan Bhatt\Desktop\IP PROJECT\Book1.csv', 'r') as file :
    reader = csv.reader(file)
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt

def piechart1():
   df=pd.read_csv('data,csv',  sep=' ', index_col=False,skipinitialspace=True\
                 ,error_bad_lines=False,encoding= 'unicode_escape')
   df=df.set_index(['Country'])
   dfl=df.iloc[:,[14]]
   final_df=dfl.sort_values(by='TotalMedal')
   final_df.reset_index(inplace=True)
   final_df.columns=('location','Total cases','Total Deaths')
   final_df=final_df.drop(11,axis='index')
   countries=df['Country']
   tmedals=df['TotalMedal']
   plt.pie(tmedals,labels=countries,explode=(0.1,0,0,0,0,0,0,0,0,0,0.2),shadow=True,autopct='%0.1f%%')
   plt.title("Olympics data analysis\nTop 10 Countries", color='b',fontsize=12)
   plt.gcf().canva.set_window_title("OLMPICS ANALYSIS")
   plt.show()

由于某种原因，我收到此错误:

AttributeError: 'DataFrameGroupBy' object has no attribute 'sort_values'

这是我一直在使用的CSV文件:

Country SummerTimesPart Sumgoldmedal    Sumsilvermedal  Sumbronzemedal  SummerTotal WinterTimesPart Wingoldmedal    Winsilvermedal  Winbronzemedal  WinterTotal TotalTimesPart  Tgoldmedal  Tsilvermedal    Tbronzemedal    TotalMedal
     Afghanistan    14  0   0   2   2   0   0   0   0   0   14  0   0   2   2
     Algeria    13  5   4   8   17  3   0   0   0   0   16  5   4   8   17
     Argentina  24  21  25  28  74  19  0   0   0   0   43  21  25  28  74
     Armenia    6   2   6   6   14  7   0   0   0   0   13  2   6   6   14

INFO-----> SummerTimesPart  :  No. of times participated in summer by each country
           WinterTimesPart  :  No. of times participated in winter by each country

Answer 1

在您的代码中，将Country设置为Index，并在此行中

dfl=df.iloc[:,[14]]

您只需选择一列 TotalMedal即可。
排序并重置索引后，您尝试按行更改列名称

final_df.columns=('location','Total cases','Total Deaths')

这是错误。.您仅过滤了一列的数据框，并且在重置后在列中也获得了 Country。因此，您在数据框中只有两列，并尝试通过提供三个值来更改列名称。
正确的行可能是-

final_df.columns=('location','TotalMedal')