[Python高效编程] - 获取天气信息并使用迭代for输出

开发环境

Python版本： python3.6

调试工具：pycharm 2017.1.3

电脑系统：Windows 10 64位系统

Python库：requests，collections

获取天气信息

import requests

def getWeather(city):
r = requests.get("http://wthrcdn.etouch.cn/weather_mini?city=" + city)
data = r.json()['data']['forecast'][0]
return '{0}: {1}, {2}'.format(city, data['low'], data['high'])

print(getWeather('武汉'))

武汉: 低温 4℃, 高温 15℃

使用可迭代对象和迭代器输出信息

from collections import Iterable, Iterator

import requests

class WeatherIterator(Iterator):
# 继承可迭代的对象
def __init__(self, cities):
self.cities = cities
self.index = 0

def getWeather(self, city):
r = requests.get("http://wthrcdn.etouch.cn/weather_mini?city=" + city)
data = r.json()['data']['forecast'][0]
return '{0}: {1}, {2}'.format(city, data['low'], data['high'])

def __next__(self):
if self.index == len(self.cities):
raise StopIteration
city = self.cities[self.index]
self.index += 1
return self.getWeather(city)

class WeatherIterable(Iterable):
# 继承迭代器
def __init__(self, cities):
self.cities = cities

def __iter__(self):
return WeatherIterator(self.cities)

for x in WeatherIterable(['北京', '上海', '武汉', '深圳']):
print(x)

北京: 低温 -4℃, 高温 7℃
上海: 低温 5℃, 高温 13℃
武汉: 低温 4℃, 高温 15℃
深圳: 低温 13℃, 高温 19℃

代码优化

上述的代码还是不够简洁，还可以进一步优化，下面重写代码

import requests

class WeatherOutput:
"""输出天气信息"""
def __init__(self, cities):
self.cities = cities
self.index = 0

def getWeather(self, city):
try:
r = requests.get("http://wthrcdn.etouch.cn/weather_mini?city=" + city)
data = r.json()['data']['forecast'][0]
return '{0}: {1}, {2}'.format(city, data['low'], data['high'])
except:
print("获取天气信息失败")

def __iter__(self):
return self

def __next__(self):
if self.index == len(self.cities):
raise StopIteration
city = self.cities[self.index]
self.index += 1
return self.getWeather(city)

for x in WeatherOutput(['北京', '上海', '武汉', '深圳']):
print(x)

北京: 低温 -4℃, 高温 7℃
上海: 低温 8℃, 高温 14℃
武汉: 低温 4℃, 高温 17℃
深圳: 低温 15℃, 高温 19℃

如果想知道原理，可以参考这篇博客：

http://blog.csdn.net/lanhaixuanvv/article/details/78503325