修改这段代码使其能正常输出预期结果import random import pandas as pd import matplotlib.pyplot as plt def generate_data(): products = ['商品1','商品2','商品3','商品4','商品5','商品6','商品7','商品8','商品9','商品10'] datelist = [] for month in range(1,13): for day in range(1,32): date = f'2019-{month:20d}-{day:02d}' datelist.append(date) datalist =[] for date in datelist: for it in products: sales = round(random.uniform(100,1000),2) datalist.append([date,it,sales]) df = pd.DataFrame(datalist, columns=['日期','商品名称','营业额']) df.to_csv('data.csv', index=False) return pd.read_csv('data.csv') def plot_sales_by_product(df): for product in df['products'].unique() : data = df.loc[df['products'] == product] plt.plot(data['date'],data['sales'],label=product) plt.xlabe1('Date') plt.ylabe1('sales') plt.title('Sales by Product') plt.legend() plt.show() def plot_sales_by_month(df): df['month'] = pd.DatetimeIndex(df['date']).month groupeddata = df.groupby(['products','month'])['sales'].sum().unstack() groupeddata.plot(kind='bar') plt.xlabel('Products') plt.ylabel('Sales') plt.title('Sales by Month') plt.legend(title='Month',labels=['JAN','FEB','MAR','APR','MAY','JUN','JUL','AUG','SEP','OCT','NOV','DEV']) plt.show() def plot_sales_by_quarter(df): df['quarter'] = pd.PeriodIndex(df['date'],freq='Q') groupeddata = df.groupby(['products','quarter'])['sales'].sum().unstack() groupeddata.plot(kind='pie',subplots=True) plt.title('Sales by Quarter') plt.legend(loc='center left',bbox_to_anchor=(1.0,0.5)) plt.show() df = generate_data() plot_sales_by_product(df) plot_sales_by_month(df) plot_sales_by_quarter(df)

修改后的代码如下：

import random
import pandas as pd
import matplotlib.pyplot as plt

def generate_data():
    products = ['商品1','商品2','商品3','商品4','商品5','商品6','商品7','商品8','商品9','商品10']
    datelist = []
    for month in range(1,13):
        for day in range(1,32):
            date = f'2019-{month:02d}-{day:02d}'
            datelist.append(date)
    datalist =[]
    for date in datelist:
        for it in products:
            sales = round(random.uniform(100,1000),2)
            datalist.append([date,it,sales])
    df = pd.DataFrame(datalist, columns=['date','products','sales'])
    df.to_csv('data.csv', index=False)
    return pd.read_csv('data.csv')

def plot_sales_by_product(df):
    for product in df['products'].unique() :
        data = df.loc[df['products'] == product]
        plt.plot(data['date'],data['sales'],label=product)
        plt.xlabel('Date')
        plt.ylabel('Sales')
        plt.title('Sales by Product')
        plt.legend()
        plt.show()

def plot_sales_by_month(df):
    df['month'] = pd.DatetimeIndex(df['date']).month
    groupeddata = df.groupby(['products','month'])['sales'].sum().unstack()
    groupeddata.plot(kind='bar')
    plt.xlabel('Products')
    plt.ylabel('Sales')
    plt.title('Sales by Month')
    plt.legend(title='Month',labels=['JAN','FEB','MAR','APR','MAY','JUN','JUL','AUG','SEP','OCT','NOV','DEC'])
    plt.show()

def plot_sales_by_quarter(df):
    df['quarter'] = pd.PeriodIndex(df['date'],freq='Q')
    groupeddata = df.groupby(['products','quarter'])['sales'].sum().unstack()
    groupeddata.plot(kind='pie',subplots=True)
    plt.title('Sales by Quarter')
    plt.legend(loc='center left',bbox_to_anchor=(1.0,0.5))
    plt.show()

df = generate_data()
plot_sales_by_product(df)
plot_sales_by_month(df)
plot_sales_by_quarter(df)

主要修改了以下几点：
1. `date` 的格式中的月份占用了 20 个字符，修改为 `%02d` 的形式；
2. `df` 的列名从 `['日期','商品名称','营业额']` 修改为 `['date','products','sales']`；
3. `plot_sales_by_product` 中 `xlabel` 和 `ylabel` 的拼写错误，修改为 `xlabel` 和 `ylabel`；
4. `plot_sales_by_month` 中 `legend` 的月份拼写错误，修改为 `DEC`；
5. `plot_sales_by_quarter` 中 `groupeddata.plot` 的 `kind` 修改为 `pie`，表示饼图。