如何按组为散点图分配颜色?
How to assign colors for scatterplot by group?
我正在尝试为数据框中的每个 class 分配颜色,这是我的代码:
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.33, random_state=42)
knn = KNeighborsClassifier(n_neighbors=7)
# fitting the model
knn.fit(X_train, y_train)
# predict the response
pred = knn.predict(X_test)
dfp = pd.DataFrame(X_test)
dfp.columns = ['SepalLengthCm', 'SepalWidthCm', 'PetalLengthCm', 'PetalWidthCm']
dfp["PClass"] = pred
pyo.init_notebook_mode()
data = [go.Scatter(x=dfp['SepalLengthCm'], y=dfp['SepalWidthCm'],
text=dfp['PClass'],
mode='markers',
marker=dict(
color=dfp['PClass']))]
layout = go.Layout(title='Chart', hovermode='closest')
fig = go.Figure(data=data, layout=layout)
pyo.iplot(data)
这是我的 df 的样子:
SepalLengthCm SepalWidthCm PetalLengthCm PetalWidthCm PClass
6.1 2.8 4.7 1.2 Iris-versicolor
5.7 3.8 1.7 0.3 Iris-setosa
7.7 2.6 6.9 2.3 Iris-virginica
所以问题是它没有根据 dfp['PClass']
列分配颜色,并且图上的每个点都是相同的颜色:黑色。即使悬停时每个点都根据其 class 正确标记。
知道为什么它不能正常工作吗?
在您的代码示例中,您尝试使用 color=dfp['PClass'])
为分类组分配颜色。这是例如 ggplot
和 ggplot(mtcars, aes(x=wt, y=mpg, shape=cyl, color=cyl, size=cyl))
应用的逻辑,其中 cyl
是分类变量。您会在页面下方看到一个示例 here。
但对于情节来说,这是行不通的。 color
in go.Scatter
将只接受数值,如 this example 和 color = np.random.randn(500)
:
为了达到您想要的结果,您必须像 this example:
中那样使用多个轨迹来构建您的绘图下面是一个使用图表对象的例子:
import numpy as np
import pandas as pd
import plotly.offline as pyo
import plotly.graph_objs as go
# Create some random data
np.random.seed(42)
random_x = np.random.randint(1, 101, 100)
random_y = np.random.randint(1, 101, 100)
# Create two groups for the data
group = []
for letter in range(0,50):
group.append("A")
for letter in range(0, 50):
group.append("B")
# Create a dictionary with the three fields to include in the dataframe
group = np.array(group)
data = {
'1': random_x,
'2': random_y,
'3': group
}
# Creat the dataframe
df = pd.DataFrame(data)
# Find the different groups
groups = df['3'].unique()
# Create as many traces as different groups there are and save them in data list
data = []
for group in groups:
df_group = df[df['3'] == group]
trace = go.Scatter(x=df_group['1'],
y=df_group['2'],
mode='markers',
name=group)
data.append(trace)
# Layout of the plot
layout = go.Layout(title='Grouping')
fig = go.Figure(data=data, layout=layout)
pyo.plot(fig)
你可以使用 plotly express 来完成。
import plotly.express as px
fig = px.scatter(dfp, x='SepalLengthCm', y='SepalWidthCm', color='PClass')