上章是講得csv，這節是json

1.如何下載資料：

以下程式碼是利用模組urllib函式urlopen()下載資料

#-*-coding:GBK-*-
#-*-coding:utf-8-*-
from __future__ import (absolute_import,division,print_function,unicode_literals)
try:
	from urllib2 import urlopen
except ImportError:
	from urllib.request import urlopen
import json
json_url='https://raw.githubusercontent.com/muxuezi/btc/master/btc_close_2017.json'
response=urlopen(json_url)
#讀取資料
req=response.read()
#將資料寫入檔案
with open('btc_close_2017_urllib.json','wb') as f:
	f.write(req)
	#載入json格式
file_urllib=json.loads(req)
print(file_urllib)
 

還可以使用第三模組request。

#-*-coding:GBK-*-
#-*-coding:utf-8-*-
import requests
json_url='https://raw.githubusercontent.com/muxuezi/btc/master/btc_close_2017.json'
req=requests.get(json_url)
with open('btc_close_2017_request.json','w') as f:
	f.write(req.txt)
file_requests=req.json()

提取相關的資料：

#-*-coding:GBK-*-
#-*-coding:utf-8-*-
import json
filename='btc_close_2017.json'
with open(filename) as f:
	btc_data=json.load(f)
#列印每天的訊息
for btc_dict in btc_data:
	date=btc_dict['date']
	month=btc_dict['month']
	week=btc_dict['week']
	weekday=btc_dict['weekday']
	close=btc_dict['close']
	print("{} is month {}week{},{},the close price is {}RMB".format(date,month,week,weekday,close))
 

匯入json模組，開啟檔案，把資料載入在btc_data裡，遍歷它 

將字元型裝變為數字值：

#-*-coding:GBK-*-
#-*-coding:utf-8-*-
import json
filename='btc_close_2017.json'
with open(filename) as f:
	btc_data=json.load(f)
#列印每天的訊息
for btc_dict in btc_data:
	date=btc_dict['date']
	month=int(btc_dict['month'])
	week=int(btc_dict['week'])
	weekday=btc_dict['weekday']
	close=int(float(btc_dict['close']))
	print("{} is month {} week {},{},the close price is {}RMB".format(date,month,week,weekday,close))
 

繪製折線圖：

#-*-coding:GBK-*-
#-*-coding:utf-8-*-
import json
import pygal
filename='btc_close_2017.json'
with open(filename) as f:
	btc_data=json.load(f)
#列印每天的訊息
dates=[]
months=[]
weeks=[]
weekdays=[]
closes=[]

for btc_dict in btc_data:
	dates.append(btc_dict['date'])
	months.append(int(btc_dict['month']))
	weeks.append(int(btc_dict['week']))
	weekdays.append(btc_dict['weekday'])
	closes.append(int(float(btc_dict['close'])))


#視覺化處理
line_chart=pygal.Line(x_label_rotation=20,show_minor_x_labels=False)
line_chart.title='收盤價'
line_chart.x_labels=dates
N=20#x軸每隔20天顯示一次
line_chart.x_labels_major=dates[::N]
line_chart.add('收盤價',closes)
line_chart.render_to_file("收盤價折線圖.svg")

 再對資料進行數學分析，找找規律

對資料進行線性分析，做對數變換

#-*-coding:GBK-*-
#-*-coding:utf-8-*-
import json
import pygal
import math

filename='btc_close_2017.json'
with open(filename) as f:
	btc_data=json.load(f)
#列印每天的訊息
dates=[]
months=[]
weeks=[]
weekdays=[]
closes=[]

for btc_dict in btc_data:
	dates.append(btc_dict['date'])
	months.append(int(btc_dict['month']))
	weeks.append(int(btc_dict['week']))
	weekdays.append(btc_dict['weekday'])
	closes.append(int(float(btc_dict['close'])))


#視覺化處理
line_chart=pygal.Line(x_label_rotation=20,show_minor_x_labels=False)
line_chart.title='收盤價對數變換'
line_chart.x_labels=dates
N=20#x軸每隔20天顯示一次
line_chart.x_labels_major=dates[::N]
closes_log=[math.log10(_) for _ in closes]
line_chart.add('log收盤價',closes_log)
line_chart.render_to_file("收盤價折線圖.svg")