python绘制趋势图的示例

import matplotlib.pyplot as plt #plt用于显示图片
import matplotlib.image as mping #mping用于读取图片
import datetime as dt
import matplotlib.dates as mdates
from pylab import *


def draw_trend_chart(dates,y):
  mpl.rcParams[\'font.sans-serif\'] = [\'SimHei\'] #指定默认字体
  mpl.rcParams[\'axes.unicode_minus\'] = False #解决保存图像是负号\'-\'显示为方块的问题
  
  x = [dt.datetime.strptime(d,\'%Y/%m/%d\').date() for d in dates]
  #plt.figure(figsize=(8,8))
  plt.figure()

  #plt.gca().xaxis.set_major_formatter(mdates.DateFormatter(\'%m/%d/%Y\'))
  #plt.gca().xaxis.set_major_locator(mdates.DayLocator())
  #plt.plot(x,y,\"r--\",linewidth=2)
  plt.plot(x,y,\"r\",linewidth=1)
  #plt.gcf().autofmt_xdate()
  
  #plt.xlabel(\"DATE\") #x轴标签
  plt.ylabel(\"WEIGHT\") #y轴标签
  plt.title(\"MY HEALTH TRACKING\")#标题

  plt.savefig(\"liuyang.png\") #保存图片名称

  lena = mping.imread(\'liuyang.png\') #读取图片文件信息
  lena.shape #（512,512,3）

  plt.imshow(lena) #显示图片
  plt.axis(\'off\') #不显示坐标轴
  plt.title(\"\")
  plt.show() #显示

def get_weight_data(filename):
  time = []
  weight = []
  fileContent=open(filename,\"r\")
  for eachline in fileContent:
    eachData = eachline.strip(\'\\n\').split(\",\")
    if eachData[-1].strip() ==\'\':
      continue
    else:
      time.append(eachData[0])
      weight.append(eachData[1])
  return [time, weight]

data = get_weight_data(\"data.csv\")
draw_trend_chart(data[0],data[1])