How can plot Artists be reused (Line2D)?

Question

How can the plot lines from `.plot` be reused in subsequent plots? I'd like to make plots on 4 axes, first three individual plot on each axes, and the last all 3 plots on last axes. Here is the code: ``` from numpy import * from matplotlib.pyplot import * fig=figure() data=arange(0,10,0.01) ax1=fig.add_subplot(2,2,1) ax2=fig.add_subplot(2,2,2) ax3=fig.add_subplot(2,2,3) ax4=fig.add_subplot(2,2,4) line1=ax1.plot(data,data) line2=ax2.plot(data, data**2/10, ls='--', color='green') line3=ax3.plot(data, np.sin(data), color='red') #could I somehow use previous plots, instead recreating them all? line4=ax4.plot(data,data) line4=ax4.plot(data, data**2/10, ls='--', color='green') line4=ax4.plot(data, np.sin(data), color='red') show() ``` The resulting picture is: Is there a way to define plots first and then add them to axes, and then plot them? Here is the logic I had in mind: ``` #this is just an example, implementation can be different line1=plot(data, data) line2=plot(data, data**2/10, ls=…

Accepted Answer

- The requested implementation in the OP doesn't work because the `Line2D` plot Artist returned by `plt.plot` can't be reused. Trying to do so, will result in a `RuntimeError` as per `def set_figure(self, fig):`

- `line1` in the OP, is not the same as `line1` created directly with the `Line2D` method, because a plotted Artist has different properties.

- In regards to `seaborn`, and API for `matplotlib`, axes-level plots like `seaborn.lineplot` return an `axes`:

- `p = sns.lineplot(...)` then `p.get_children()` to get the Artist objects.

- Plot artists can be created directly, with methods like `matplotlib.lines.Line2D`, and reused in multiple plots.

- Updated code using standard importing practices, subplots, and not using a list-comprehension for a side-effect (a python anti-pattern).

- Tested in `python 3.8.11`, `matplotlib 3.4.3`

```
import numpy as np
from copy import copy
import matplotlib.pyplot as plt
from matplotlib.lines import Line2D

# crate the figure and subplots
fig, axes = plt.subplots(2, 2)

# flatten axes into 1-D for easy indexing and iteration
axes = axes.ravel()

# test data
data=np.arange(0, 10, 0.01)

# create test lines
line1 = Line2D(data, data)
line2 = Line2D(data, data**2/10, ls='--', color='green')
line3 = Line2D(data, np.sin(data), color='red')
lines = [line1, line2, line3]

# add the copies of the lines to the first 3 subplots
for ax, line in zip(axes[0:-1], lines):
    ax.add_line(copy(line))

# add 3 lines to the 4th subplot
for line in lines:
    axes[3].add_line(line)
    
# autoscale all the subplots if needed
for _a in axes:
    _a.autoscale()

plt.show()
```

Original Answer

- Here is one possible solution. I'm not sure that it's very pretty, but at least it does not require code duplication.

```
import numpy as np, copy
import matplotlib.pyplot as plt, matplotlib.lines as ml

fig=plt.figure(1)
data=np.arange(0,10,0.01)
ax1=fig.add_subplot(2,2,1)
ax2=fig.add_subplot(2,2,2)
ax3=fig.add_subplot(2,2,3)
ax4=fig.add_subplot(2,2,4)

#create the lines
line1=ml.Line2D(data,data)
line2=ml.Line2D(data,data**2/10,ls='--',color='green')
line3=ml.Line2D(data,np.sin(data),color='red')
#add the copies of the lines to the first 3 panels
ax1.add_line(copy.copy(line1))
ax2.add_line(copy.copy(line2))
ax3.add_line(copy.copy(line3))

[ax4.add_line(_l) for _l in [line1,line2,line3]] # add 3 lines to the 4th panel

[_a.autoscale() for _a in [ax1,ax2,ax3,ax4]] # autoscale if needed
plt.draw()
```

How can plot Artists be reused (Line2D)?

Solution

Problem

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