title: How to add the volume bar charts in python?
body: <p>Hello I do this code to see the Candlestick Chart on the crypto currencies on Bittrex, but I would like to add the volume. How can I do this ? </p>
  
  <p>At the beginning of my code I get the data from a JSON URL, which allows me to have the candlestick chart and when I get the data, I save the volume in 
  <code>float(data['result'][i]['V'])</code> but I don't know how to plot the volume ...</p>
  
  <p>Here is my code :</p>
  
  <pre><code>import urllib2
  import json
  from matplotlib.finance import candlestick2_ohlc
  import matplotlib.pyplot as plt
  import matplotlib.ticker as ticker
  import datetime as datetime
  import numpy as np
  
  l = []
  date = []
  date_intermediaire = []
  
  response = urllib2.urlopen('https://bittrex.com/Api/v2.0/pub/market/GetTicks?marketName=BTC-ETH&amp;tickInterval=thirtyMin&amp;_=')
  data = json.load(response)
  print data
  
  
  for i in range(len(data['result'])-95,len(data['result'])):
      append_me = float(data['result'][i]['O']), float(data['result'][i]['H']), float(data['result'][i]['L']), float(data['result'][i]['C']), float(data['result'][i]['V'])
      l.append((append_me))
      date.append(data['result'][i]['T'])
  
  ohlc = np.array(l, dtype=[('open', '&lt;f4'), ('high', '&lt;f4'), ('low', '&lt;f4'), ('close', '&lt;f4'), ('volume', '&lt;f4')])
  
  
  for i in range(0,len(date)):
      date[i] = datetime.datetime.strptime(date[i], "%Y-%m-%dT%H:%M:%S")
      date_intermediaire.append((date[i]-datetime.datetime(1970,1,1)).total_seconds())
  
  
  
  
  xdate = [datetime.datetime.fromtimestamp(i) for i in date_intermediaire]
  
  
  
  
  fig, ax = plt.subplots()
  candlestick2_ohlc(ax,ohlc['open'],ohlc['high'],ohlc['low'],ohlc['close'],width=0.6)
  
  
  
  ax.xaxis.set_major_locator(ticker.MaxNLocator(6))
  
  
  def mydate(x,pos):
      try:
          return xdate[int(x)]
      except IndexError:
          return ''
  
  
  ax.xaxis.set_major_formatter(ticker.FuncFormatter(mydate))
  
  fig.autofmt_xdate()
  fig.tight_layout()
  plt.savefig("test.png")
  </code></pre>
  
  <p>This is the results of my code, so far:</p>
  
  <p><img src="https://i.stack.imgur.com/WFcNe.png" alt="candlesticks"></p>