堆积面积图的问题，一直显示百分比堆积面积图？

Question

So I've spent about 10 hours on this simple task already, I'm out of patience. I'm unable to get the chart I want.

What I want:

What I get:

Yes I am using percentages, but I do not want my chart to be full, I just want the percentages to be stacked one on top of eachother.

My code:

plt.figure()
plt.stackplot(unique_years, my_percentages[:, 0], my_percentages[:, 1],my_percentages[:, 2], labels=['Petrol','Diesel', 'Hybrid'])
plt.legend(loc='upper left')
plt.show()

The my_percentage is a numpy table with 3 columns named 0,1 and 2, each representing a type of fuel as a percentage.

Unique_years is an array for each unique year (1997-2020).

Can anybody please help? I am desperate lol

Answer 1

You need to put the three lists into a list:

from matplotlib import pyplot as plt
import numpy as np

unique_years = np.arange(1997, 2021)
my_values = np.random.rand(len(unique_years), 5)
my_percentages = 100 * my_values / my_values.sum(axis=1, keepdims=True)
plt.stackplot(unique_years, [my_percentages[:, 0], my_percentages[:, 1], my_percentages[:, 2]])
plt.show()

Or you could just transpose the percentages array:

from matplotlib import pyplot as plt
from matplotlib.ticker import PercentFormatter
import numpy as np

unique_years = np.arange(1997, 2021)
my_values = np.random.rand(len(unique_years), 5)
my_percentages = 100 * my_values / my_values.sum(axis=1, keepdims=True)
plt.stackplot(unique_years, my_percentages.T[:3], labels=['fuel a', 'fuel b', 'fuel c'], colors=plt.cm.Set2.colors[:3])
plt.margins(x=0)
plt.gca().yaxis.set_major_formatter(PercentFormatter(100))
plt.legend(loc='upper left', bbox_to_anchor=[1.02, 1.02])
plt.tight_layout()
plt.show()