Python 2 中的注释函数的困难

Question

我正在尝试通过串行端口从arduino 在 Python 上绘制实时数据。

我发现annotate功能有一些困难：我不知道如何配置它，也不知道我放置annotate功能的地方是否正确。

import serial
import time
import numpy
import matplotlib.pyplot as plt
from drawnow import *

temperature= []
vitesse= []
charge= []
current= []
Time = []
cnt=0

# Create our serial object
arduinoData = serial.Serial('com5', 9600) 

# Turn on matplotlib interactive mode to plot live data
plt.ion() 

##fig1 = plt.figure()
STARTINGTIME = round(time.time(),2)

# A function that makes our desired plot
def makeFig(): 
    plt.subplot(2,2,1)
    plt.subplot(2,2,1).annotate(str(temperature)+','+ str(Time), 
                                textcoords='offset points')
    plt.title('Live Streaming Temperature Sensor Data')
    plt.ylabel('Temperature C')
    plt.grid(True)
    plt.plot(temperature, 'ro-')

    plt.subplot(2,2,2)
    plt.subplot(2,2,2).annotate(str(vitesse)+','+ str(Time), 
                                textcoords='offset points')
    plt.title('Live Streaming Speed Sensor Data')
    plt.ylabel('Speed KM/H')
    plt.grid(True)
    plt.plot(vitesse, 'bo-')

    plt.subplot(2,2,3)
    plt.subplot(2,2,3).annotate(str(charge)+','+ str(Time), 
                                textcoords='offset points')
    plt.title('Live Streaming SOC Sensor Data')
    plt.ylabel('Battery Charge %')
    plt.grid(True)
    plt.plot(charge, 'go-')

    plt.subplot(2,2,4)
    plt.subplot(2,2,4).annotate(str(current)+','+ str(Time), 
                                textcoords='offset points')
    plt.title('Live Streaming Current Sensor Data')
    plt.ylabel('Current A')
    plt.grid(True)
    plt.plot(current, 'yo-')

while True:

    while (arduinoData.inWaiting()==0): 
        # Wait here until there is data
        pass

    # Read the line of text from the serial port
    arduinoString = arduinoData.readline() 
    # Split it into an array
    dataArray = arduinoString.split(';')   
    temp = float(dataArray[0])
    vite = float(dataArray[1])
    char = float(dataArray[2])
    curr = float(dataArray[3])

    # Build our temperature array by appending temperature readings
    temperature.append(temp) 
    # Build our vitesse array by appending temp readings
    vitesse.append(vite)                    
    # Build our charge array by appending temp readings 
    charge.append(char)                     
    # Build our current array by appending temp readings
    current.append(curr)                     

    Time.append(round(time.time(),2) - STARTINGTIME)

    # Update our live graph
    drawnow(makeFig)                       

    plt.pause(0.00001)
    cnt += 1
    if(cnt > 50):
        temperature.pop(0)
        vitesse.pop(0)
        charge.pop(0)
        current.pop(0)

Answer 1

annotate 至少需要两个参数。第一个是文本，第二个是一个元组，其中包含您希望文本所在的坐标。此外，由于您要注释每个点，因此您需要在循环中调用 annotate。

这是一个例子：

import matplotlib.pyplot as plt
import numpy as np
Y = np.sin(np.linspace(0, 3, 10))
plt.plot(Y)
for i, y in enumerate(Y):
    plt.annotate(str(y), (i, y))
plt.show()

下面是循环在代码中的位置：

def makeFig(): #Create a function that makes our desired plot

    plt.subplot(2,2,1)
    plt.title('Live Streaming Temperature Sensor Data')
    plt.ylabel('Temperature C')
    plt.grid(True)
    plt.plot(temperature, 'ro-')
    for i, t in enumerate(temperature):
        plt.annotate(str(t), (i, t), textcoords='offset points')