python-matplotlib读取csv文件数据画折线图

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.dates as mdates
# np.set_printoptions(threshold=np.inf) # 去掉print省略的内容
 
# 导入数据
time,id,info=np.loadtxt(‘20190711.csv‘,dtype=str,delimiter=‘,‘,usecols=(0,1,2),unpack=True)
vmcId = np.str_("0x1028d0d4")


# i为匹配ID的帧数量
i = 0
count = 0
while (count < np.size(time)):
    if id[count] == vmcId:
        i = i + 1
    count = count + 1

# 创建数组
print(i)
engineTime = np.zeros(i) 
engineSpeed = np.zeros(i, dtype = np.int) 
vehicleSpeed = np.zeros(i, dtype = np.int) 

# 将数据保存至数组
i = 0
count = 0
while (count < np.size(time)):
    if id[count] == vmcId:
        engineTime[i] =  float(time[count])
        engineSpeed[i] = int(info[count][11:13]+info[count][9:11],16)
        vehicleSpeed[i] = engineSpeed[i]/7.42/60*1.96*3.6
        i = i + 1
    count = count + 1

plt.figure(1)                # 第一个图形
plt.subplot(2,1,1)             # 第一个图形的第一个子图。看成2行1列，当前为第1行
plt.plot(engineTime,engineSpeed,linewidth=0.5) 

plt.subplot(2,1,2)             # 第一个图形的第二个子图
plt.plot(engineTime,vehicleSpeed,linewidth=0.5)  

plt.figure(2)                # 第一个图形
# 默认subplot(1,1,1) 
plt.plot(engineTime,engineSpeed,‘g-‘,linewidth=0.5) 

plt.show()