Matplotlib用与系列相对应的颜色创建文本

Question

I am trying to create a plot with different colors for different series. The question arose when I tried to add the data in the figure as a text box.

The code I used is as follows:

import pandas as pd
import matplotlib.pyplot as plt
import seaborn as sns
import numpy as np
import scipy.stats as stats

df = pd.DataFrame({'x': [21000, 16900, 18200, 32000, 35000, 7500], 'y':[3000, 2100, 1500, 3000, 2500, 2000], 'z':['a', 'b', 'c', 'd', 'e', 'f']})

fig, ax = plt.subplots(figsize=(8,6))

text_list = []
color_list = []

for i, row in df.iterrows():
    mu, sigma, group = row['x'], row['y'], row['z']       
    x = np.linspace(mu - 4*sigma, mu + 4*sigma, 100)

    sns.lineplot(x, stats.norm.pdf(x, mu, sigma), ax=ax)
    color = ax.get_lines()[-1].get_c()

    ax = plt.gca()
    ax.text(mu*1.05, max(stats.norm.pdf(x, mu, sigma)), group, fontsize=16, color=color) #only retrieve RGB so blank text is not too light      

    text = r'{0}: {1} $\pm$ {2}'.format(group, mu, sigma)
    text_list.append(text)
    color_list.append(color)

plt.gcf().text(0.68, 0.6, '\n'.join(text_list), bbox=dict(facecolor='white', edgecolor='black', pad=10.0, alpha=1), fontsize=14)
fig.show()

Which produces the following graph:

The texts within the bbox are all black. Ideally, each line in the text box should have a color identical to the corresponding series in the plot.

I was able to save two lists of texts and colors in the text_box_content and color_list. I also tried to add plt.gcf().text() within the for loop with dynamically-updated text locations, but the bounding boxes are created for each row instead of an overall-bounding box for all text.

It would be nicer if there is something conceptually similar to

plt.gcf().text(zip(text_list, color_list)) so each line can have its own color?

Answer 1

You could create a legend and colorize each legend item by the color of the line it belongs to. If you don't want to show the line itself in the legend, you could instead show the corresponding letter as a legend handle.

import pandas as pd
import matplotlib.pyplot as plt
from matplotlib.legend_handler import HandlerBase
from matplotlib.text import Text
import seaborn as sns
import numpy as np
import scipy.stats as stats

class TextHandler(HandlerBase):
    def create_artists(self, legend,tup ,xdescent, ydescent,
                        width, height, fontsize,trans):
        tx = Text(width/2.,height/2,tup[0], fontsize=fontsize,
                  ha="center", va="center", color=tup[1], fontweight="bold")
        return [tx]

df = pd.DataFrame({'x': [21000, 16900, 18200, 32000, 35000, 7500], 
                   'y':[3000, 2100, 1500, 3000, 2500, 2000], 
                   'z':['a', 'b', 'c', 'd', 'e', 'f']})

fig, ax = plt.subplots(figsize=(8,6))

handles = []
labels = []

for i, row in df.iterrows():
    mu, sigma, group = row['x'], row['y'], row['z']       
    x = np.linspace(mu - 4*sigma, mu + 4*sigma, 100)

    sns.lineplot(x, stats.norm.pdf(x, mu, sigma), ax=ax)
    color = ax.get_lines()[-1].get_c()

    ax.text(mu*1.05, max(stats.norm.pdf(x, mu, sigma)), group, fontsize=16, color=color)

    handles.append(("{}:".format(group), color))
    labels.append("{} $\pm$ {}".format(mu, sigma))

leg = ax.legend(handles=handles, labels=labels, handler_map={tuple : TextHandler()},
          facecolor='white', edgecolor='black', borderpad=0.9, framealpha=1, 
          fontsize=10, handlelength=0.5)

for h, t in zip(leg.legendHandles, leg.get_texts()):
    t.set_color(h.get_color())

plt.show()

This is inspired by and makes partial use of the code from my answer to this question , which also holds an alternative in case you do not want to use a legend.