每月最后一天的汇总

以下是一个示例代码，演示了如何获取每月最后一天的汇总。

import pandas as pd

# 创建一个示例数据集
data = {'日期': pd.date_range(start='1/1/2022', end='12/31/2022', freq='D'),
        '销售额': [100, 200, 150, 300, 250, 400, 350, 500, 450, 600, 550, 700,
                  650, 800, 750, 900, 850, 1000, 950, 1100, 1050, 1200, 1150,
                  1300, 1250, 1400, 1350, 1500, 1450, 1600, 1550, 1700, 1650,
                  1800, 1750, 1900, 1850, 2000, 1950, 2100, 2050, 2200, 2150,
                  2300, 2250, 2400, 2350, 2500, 2450, 2600, 2550, 2700, 2650,
                  2800, 2750, 2900, 2850, 3000, 2950, 3100, 3050, 3200, 3150,
                  3300, 3250, 3400, 3350, 3500, 3450, 3600, 3550, 3700, 3650,
                  3800, 3750, 3900, 3850, 4000, 3950, 4100, 4050, 4200, 4150,
                  4300, 4250, 4400, 4350, 4500, 4450, 4600, 4550, 4700, 4650,
                  4800, 4750, 4900, 4850, 5000, 4950, 5100, 5050, 5200, 5150,
                  5300, 5250, 5400, 5350, 5500, 5450, 5600, 5550, 5700, 5650,
                  5800, 5750, 5900, 5850, 6000, 5950, 6100, 6050, 6200, 6150,
                  6300, 6250, 6400, 6350, 6500, 6450, 6600, 6550, 6700, 6650,
                  6800, 6750, 6900, 6850, 7000, 6950, 7100, 7050, 7200, 7150,
                  7300, 7250, 7400, 7350, 7500, 7450, 7600, 7550, 7700, 7650,
                  7800, 7750, 7900, 7850, 8000, 7950, 8100, 8050, 8200, 8150,
                  8300, 8250, 8400, 8350, 8500, 8450, 8600, 8550, 8700, 8650,
                  8800, 8750, 8900, 8850, 9000, 8950, 9100, 9050, 9200, 9150,
                  9300, 9250, 9400, 9350, 9500, 9450, 9600, 9550, 9700, 9650,
                  9800, 9750, 9900, 9850, 10000, 9950, 10100, 10050, 10200, 10150,
                  10300, 10250, 10400, 10350, 10500, 10450, 10600, 10550, 10700, 10650,
                  10800, 10750, 10900, 10850, 11000, 10950, 11100, 11050, 11200, 11150,
                  11300, 11250, 11400, 11350, 11500, 11450, 116