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efueyo
Asked: 2020-04-17 06:10:46 +0800 CST 2020-04-17 06:10:46 +0800 CST

Fill a portion of a curved graph with color

  • 772

As an example, I attach the code to draw the graph of a normal distribution. I have managed to fill its entire interior with color, but what I really want is to fill only from the extreme left to the ordered one marked with the letter "a".

import pandas as pd
from scipy import stats
import matplotlib.pyplot as plt # importando matplotlib
# Graficando Normal

etiquetas = "Z"
x_pos = [1]
mu, sigma = 0, 1 # media y desvio estandar
normal = stats.norm(mu, sigma)
x = np.linspace(normal.ppf(0.01),
                normal.ppf(0.99), 100) # función e densidad de probabilidad

fp = normal.pdf(x) # Función de Probabilidad
plt.plot(x, fp)
plt.xticks(x_pos, etiquetas) 
plt.fill_between(x  , fp, facecolor="green", alpha= 0.2)
plt.vlines(1, ymin= 0,  ymax= 0.25, color = "blue", linestyles ="--")
plt.title('Distribución Normal')
plt.ylabel('probabilidad')
plt.xlabel('valores')
plt.show()

I will appreciate your suggestions.

pandas

1 Answers

  1. Best Answer

    You must use the argument whereof matplotlib.pyplot.fill_betweento indicate a condition based on the values ​​of the axis x, yor both:

    from scipy import stats
import matplotlib.pyplot as plt # importando matplotlib
import numpy as np


# Graficando Normal
etiquetas = "Z"
x_pos = [1]
mu, sigma = 0, 1 # media y desvio estandar
normal = stats.norm(mu, sigma)
x = np.linspace(normal.ppf(0.01),
                normal.ppf(0.99), 100) # función e densidad de probabilidad

fp = normal.pdf(x) # Función de Probabilidad
plt.plot(x, fp)
plt.xticks(x_pos, etiquetas) 
xi = np.interp(0.25, x, fp)
plt.vlines(1, ymin= 0,  ymax= 0.25, color = "blue", linestyles ="--")
plt.fill_between(x, fp, where=x <= 1, facecolor="green", alpha= 0.2)
plt.title('Distribución Normal')
plt.ylabel('probabilidad')
plt.xlabel('valores')
plt.show()

    enter image description here

    If you want to fill between two values ​​of x, since you use NumPy you should do:

    plt.fill_between(
    x, fp, where=(0.5 <= x) & (x <= 1.5), facecolor="green", alpha= 0.2
    )

    enter image description here

    • 2