瀑布图是由麦肯锡顾问公司所独创的图表类型，因为形似瀑布流水而称之为瀑布图( waterfall plot)。此种图表采用绝对值与相对值结合的方式，多适用于表达多个特定数值之间的数量变化关系。本文简单介绍如何利用python绘制该图。
命令如下
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')
输出如下
以上就是【python教程】绘制瀑布图的内容。