问题描述

如何利用 plotly.express 在一个 Pandas 数据框的两个 y 轴上绘制多条线?

How do I utilize plotly.express to plot multiple lines on two yaxis out of one Pandas dataframe?

我发现这对于绘制包含特定子字符串的所有列非常有用:

I find this very useful to plot all columns containing a specific substring:

    fig = px.line(df, y=df.filter(regex="Linear").columns, render_mode="webgl")

因为我不想遍历所有过滤后的列并使用类似的东西:

as I don't want to loop over all my filtered columns and use something like:

    fig.add_trace(go.Scattergl(x=df["Time"], y=df["Linear-"]))

在每次迭代中.

推荐答案

我花了一些时间来解决这个问题，但我觉得这对某些人可能有用.

It took me some time to fiddle this out, but I feel this could be useful to some people.

# import some stuff
import plotly.express as px
from plotly.subplots import make_subplots
import pandas as pd
import numpy as np

# create some data
df = pd.DataFrame()
n = 50
df["Time"] = np.arange(n)
df["Linear-"] = np.arange(n)+np.random.rand(n)
df["Linear+"] = np.arange(n)+np.random.rand(n)
df["Log-"] = np.arange(n)+np.random.rand(n)
df["Log+"] = np.arange(n)+np.random.rand(n)
df.set_index("Time", inplace=True)

subfig = make_subplots(specs=[[{"secondary_y": True}]])

# create two independent figures with px.line each containing data from multiple columns
fig = px.line(df, y=df.filter(regex="Linear").columns, render_mode="webgl",)
fig2 = px.line(df, y=df.filter(regex="Log").columns, render_mode="webgl",)

fig2.update_traces(yaxis="y2")

subfig.add_traces(fig.data + fig2.data)
subfig.layout.xaxis.title="Time"
subfig.layout.yaxis.title="Linear Y"
subfig.layout.yaxis2.type="log"
subfig.layout.yaxis2.title="Log Y"
# recoloring is necessary otherwise lines from fig und fig2 would share each color
# e.g. Linear-, Log- = blue; Linear+, Log+ = red... we don't want this
subfig.for_each_trace(lambda t: t.update(line=dict(color=t.marker.color)))
subfig.show()

技巧

subfig.for_each_trace(lambda t: t.update(line=dict(color=t.marker.color)))

我是从 nicolaskruchten 那里得到的:https://stackoverflow.com/a/60031260

I got from nicolaskruchten here: https://stackoverflow.com/a/60031260

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