Let's make a decent python waterfall chart function. Original starter code taken from Chris Moffitt's page at http://pbpython.com/waterfall-chart.html
----------------- original at time of project start ----------------
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
from matplotlib.ticker import FuncFormatter
#Use python 2.7+ syntax to format currency def money(x, pos): 'The two args are the value and tick position' return "${:,.0f}".format(x) formatter = FuncFormatter(money)
#Data to plot. Do not include a total, it will be calculated index = ['sales','returns','credit fees','rebates','late charges','shipping'] data = {'amount': [350000,-30000,-7500,-25000,95000,-7000]}
#Store data and create a blank series to use for the waterfall trans = pd.DataFrame(data=data,index=index) blank = trans.amount.cumsum().shift(1).fillna(0)
#Get the net total number for the final element in the waterfall total = trans.sum().amount trans.loc["net"]= total blank.loc["net"] = total
#The steps graphically show the levels as well as used for label placement step = blank.reset_index(drop=True).repeat(3).shift(-1) step[1::3] = np.nan
#When plotting the last element, we want to show the full bar, #Set the blank to 0 blank.loc["net"] = 0
#Plot and label my_plot = trans.plot(kind='bar', stacked=True, bottom=blank,legend=None, figsize=(10, 5), title="2014 Sales Waterfall") my_plot.plot(step.index, step.values,'k') my_plot.set_xlabel("Transaction Types")
#Format the axis for dollars my_plot.yaxis.set_major_formatter(formatter)
#Get the y-axis position for the labels y_height = trans.amount.cumsum().shift(1).fillna(0)
#Get an offset so labels don't sit right on top of the bar max = trans.max() neg_offset = max / 25 pos_offset = max / 50 plot_offset = int(max / 15)
#Start label loop loop = 0 for index, row in trans.iterrows(): # For the last item in the list, we don't want to double count if row['amount'] == total: y = y_height[loop] else: y = y_height[loop] + row['amount'] # Determine if we want a neg or pos offset if row['amount'] > 0: y += pos_offset else: y -= neg_offset my_plot.annotate("{:,.0f}".format(row['amount']),(loop,y),ha="center") loop+=1
#Scale up the y axis so there is room for the labels my_plot.set_ylim(0,blank.max()+int(plot_offset)) #Rotate the labels my_plot.set_xticklabels(trans.index,rotation=0) my_plot.get_figure().savefig("waterfall.png",dpi=200,bbox_inches='tight')
--------------------- EOF ---------------------