基于来自 CSV 的输入字段使用 matplotlib.pyplot 的多色散点图

Question

我想要一个散点图，其中每个点都根据标签着色：相同的标签应使用相同颜色的点绘制。

eg: tag: 'One', color : red
    tag: 'Two', color : green

输入 CSV 文件：（第一列是标签）

One;0;0.2345;0.43543;
Two;0.2345;0;0.34563;
One;0.43543;0.34563;0;

绘图代码：

import csv
import numpy as np
import matplotlib.pyplot as plt
from sklearn import manifold
reader = csv.reader(open("data.csv", "r"), delimiter=';')
data = list(reader)

dists = []
tags = []
for d in data:
    tags.append(d[0])
    dists.append(map(float , d[1:-1]))

adist = np.array(dists)
amax = np.amax(adist)
adist /= amax

mds = manifold.MDS(n_components=2, dissimilarity="precomputed", random_state=10)
results = mds.fit(adist)

coords = results.embedding_

plt.subplots_adjust(bottom = 0.1)
plt.scatter(coords[:, 0], coords[:, 1], marker = 'o')
for label, x, y in zip(tags, coords[:, 0], coords[:, 1]):
    plt.annotate(
        label,
        xy = (x, y), xytext = (-8, 8),
        textcoords = 'offset points', ha = 'right', va = 'bottom',
        bbox = dict(boxstyle = 'round,pad=0.2', fc = 'blue', alpha = 0.1),
        arrowprops = dict(arrowstyle = '->', connectionstyle = 'arc3,rad=0'))

plt.show()

现在所有显示的点都是同一种颜色。我希望每个点都具有不同的颜色，基于标签的字符串值。可以从 python

中的地图中选择颜色

{one:red, two:green, three:yellow}

Answer 1

由于您不仅仅是在代码中绘图，我将建议一个对您的代码进行最少更改的解决方案，以便您可以轻松地合并它：

为颜色选择创建字典：color_dict = {'One':'red', 'Two':'green', 'Three':'yellow'}
通过将 plt.scatter() 移动到 for 循环并将其更改为 plt.scatter(x, y, c=color_dict[label], marker = 'o')

一个完整的更新示例及其结果：

import csv
import numpy as np
import matplotlib.pyplot as plt
from sklearn import manifold
reader = csv.reader(open("data.csv", "r"), delimiter=';')
data = list(reader)

dists = []
tags = []
for d in data:
    tags.append(d[0])
    dists.append(map(float , d[1:-1]))

adist = np.array(dists)
amax = np.amax(adist)
adist /= amax

mds = manifold.MDS(n_components=2, dissimilarity="precomputed", random_state=10)
results = mds.fit(adist)

coords = results.embedding_

color_dict = {'One':'red', 'Two':'green', 'Three':'yellow'}

plt.subplots_adjust(bottom = 0.1)
#plt.scatter(coords[:, 0], coords[:, 1], marker = 'o')
for label, x, y in zip(tags, coords[:, 0], coords[:, 1]):
    plt.scatter(x, y, c=color_dict[label], marker = 'o')
    plt.annotate(
        label,
        xy = (x, y), xytext = (-8, 8),
        textcoords = 'offset points', ha = 'right', va = 'bottom',
        bbox = dict(boxstyle = 'round,pad=0.2', fc = 'blue', alpha = 0.1),
        arrowprops = dict(arrowstyle = '->', connectionstyle = 'arc3,rad=0'))

plt.show()

基于来自 CSV 的输入字段使用 matplotlib.pyplot 的多色散点图

Multi color scatter plot using matplotlib.pyplot based on input field from CSV

python

plot

matplotlib

scatter-plot