python打开csv文件绘制折线图_Python入门--利用matplotlib导入csv数据绘制折线图（2）...

目标一：制作两个城市最高温和最低温对比图

# 代码如下：

import matplotlib.pyplot as plt

from datetime import datetime

import csv

def get_weather_data(filename, dates, highs, lows):

'''get the highs and lows from a data file'''

with open(filename) as f:

reader = csv.reader(f)

header_row = next(reader)

for row in reader:

try:

current_date = datetime.strptime(row[0], '%Y-%m-%d')

high = int(row[1])

low = int(row[3])

except ValueError:

print(current_date, 'missing data')

else:

dates.append(current_date)

highs.append(high)

lows.append(low)

# Get weather data for Sitka

dates, highs, lows = [], [], []

get_weather_data('sitka_weather_2014.csv', dates, highs, lows)

# Plot weather data for Sitka

fig = plt.figure(dpi=128, figsize=(10,6))

plt.plot(dates, highs, c='red', alpha=0.6)

plt.plot(dates, lows, c='blue', alpha=0.6