每次向我的csv文件中添加新值时，我都会运行这个脚本进行更新（这是一个从机器中获取值的手动日志）：

from itertools import count
import pandas as pd
import matplotlib.pyplot as plt
from matplotlib.animation import FuncAnimation

plt.style.use('fivethirtyeight')

x_vals = []
y_vals = []

counter=0
index = count()

def animate(i):
    data = pd.read_csv('C:/Users/Owner/Downloads/Manual-Log-27Nov2020-150846.csv')
    data=data.dropna()
    data['Date And Time']=data['Date']+' '+data['Time']
    Date = data['Date And Time']
    Temp = data['Temperature']
    Pressure = data['Pressure']
    pH = data['pH']

    plt.cla()

    plt.plot(Date, Temp, label='Temperature')
    plt.plot(Date, Pressure, label='Pressure')
    plt.plot(Date, pH, label='pH')

    plt.legend(loc='upper left')
    plt.xlabel('Date and Time')
    plt.ylabel('Y Values')
    plt.xticks(rotation=90)

    plt.tight_layout()

ani = FuncAnimation(plt.gcf(), animate, interval=30000)

plt.tight_layout()
plt.show()

由于它是一个如此大的文件（20k行左右），因此生成的图形非常庞大，您无法真正正确地读取数据。有没有办法我只能让它显示最近的20个读数？