In this post we will show you how to generate a candlestick chart in Python using the Bokeh module. To install the Bokeh module you will need to in type pip install bokeh in your command line on a PC or the Mac terminal. Once you have installed the package you can use the below code to generate a candlestick chart using Bokeh.

First import the packages

#Import the packages
import pandas as pd
import pandas_datareader as web
from bokeh.plotting import figure, show, output_file

Next download the price data for the SPY etf. Our start date is March 1, 2018.

spy_price = web.get_data_yahoo("SPY",start = "2018-03-01", end = "2018-05-15")

spy_price['date'] = pd.to_datetime(spy_price.index)
# This is to color the red and green bars for Down and up days
increase = spy_price['Close'] > spy_price["Open"]
decrease = spy_price['Open'] > spy_price["Close"]
# w is used to specify the width of each bar
w = 12*60*60*1000
# Tools we want on our chart such as zoom, save etc
tools = "pan,box_zoom,reset,save"
# p is our figure or plot
p = figure(x_axis_type = "datetime", tools = tools, plot_width = 1000, title = "SPY CandleStick Chart")
# Shows the grid line traperency
p.grid.grid_line_alpha=0.3
# Adding Vertical lines on the cheart each day
p.segment(spy_price.date, spy_price.High, spy_price.date, spy_price.Low, color="black")
# Adding the bars on each line and specifying the width as w
# Coloring up days as Green
p.vbar(spy_price.date[increase], w, spy_price.Open[increase], spy_price.Close[increase], fill_color="#D5E1DD", line_color="black")
# Coloring down days as Red
p.vbar(spy_price.date[decrease], w, spy_price.Open[decrease], spy_price.Close[decrease], fill_color="#F2583E", line_color="black")
# Saving the file as candlestick.html
output_file("candlestick.html", title="candlestick.py example")
show(p) 

Once we have generated the chart we can use the show(p) to show the chart