Home >Backend Development >Python Tutorial >[Python Tutorial] Drawing a Waterfall Chart
Waterfall chart is a chart type originally created by McKinsey Consulting Company. It is called Waterfall Plot because it looks like a waterfall. This kind of chart uses a combination of absolute value and relative value, and is mostly suitable for expressing the quantitative relationship between multiple specific values. This article briefly introduces how to draw this graph using Python.
The command is as follows
1)导入程序包 import numpy as np import pandas as pd import matplotlib.pyplot as plt from matplotlib.ticker import FuncFormatter 2)导入及清理数据 def money(x, pos): return "${:,.0f}".format(x) formatter = FuncFormatter(money) index = ['sales','returns','credit fees','rebates','late charges','shipping'] data = {'amount': [350000,-30000,-7500,-25000,95000,-7000]} trans = pd.DataFrame(data=data,index=index) blank = trans.amount.cumsum().shift(1).fillna(0) total = trans.sum().amount trans.loc["net"]= total blank.loc["net"] = total step = blank.reset_index(drop=True).repeat(3).shift(-1) step[1::3] = np.nan blank.loc["net"] = 0 3)绘制图像 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") my_plot.yaxis.set_major_formatter(formatter) y_height = trans.amount.cumsum().shift(1).fillna(0) max = trans.max() neg_offset = max / 25 pos_offset = max / 50 plot_offset = int(max / 15) loop = 0 for index, row in trans.iterrows(): if row['amount'] == total: y = y_height[loop] else: y = y_height[loop] + row['amount'] if row['amount'] > 0: y += pos_offset else: y -= neg_offset my_plot.annotate("{:,.0f}".format(row['amount']),(loop,y),ha="center") loop+=1 my_plot.set_ylim(0,blank.max()+int(plot_offset)) my_plot.set_xticklabels(trans.index,rotation=0) my_plot.get_figure().savefig("waterfall.png",dpi=200,bbox_inches='tight')
The output is as follows
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