如何在此瀑布图上简化和创建条件颜色？

Question

这是瀑布图的代码。我想问一下：

如果有办法简化这段代码。代码太长了，我敢肯定还有很多额外的代码行可以减少。
如何使第一个和最后一个条变黑？。由于我正在创建瀑布图，因此我希望第一个和最后一个值始终为黑色，中间的值为绿色或红色，具体取决于它是负数还是正数。
大于零的绿色条。
小于零的柱红色。

如有任何帮助，我们将不胜感激。

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')

Answer 1

问题 2、3 和 4 的答案：绘制后设置条形图块的颜色：

for p, c in zip(my_plot.containers[0].patches, np.r_[0, np.sign(trans.amount[1:-1]), 0]):
    p.set_color({0: 'k', 1: 'g', -1: 'r'}[c])

如何在此瀑布图上简化和创建条件颜色？

How can I simplify and create conditional colours on this Waterfall Chart?

python

numpy

matplotlib

pandas

powerbi