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Setup: Anaconda 3 (Win10 64), Spyder 4 and Python 3.7. The IPython Graphics setting is default (Inline).I'm still a new to Python but I've looked around and have not found an answer that solves my problem so far. Thanks everyone in advance.

So in this setup, whenever I create a plot using matplotlib, it appears in the plot pane of Spyder. e.g.

import pandas as pd
import matplotlib.pyplot as plt
import numpy as np

df = pd.DataFrame(np.random.randint(0,100,size=(100, 1)), columns=list('A'))
bp = df.boxplot(column = 'A')

creates a boxplot. Now, if I want to add a title to the plot, the code would be 

bp.set_title("This Title")

This is where I'm getting some problems. If I run the entire block together 

df = pd.DataFrame(np.random.randint(0,100,size=(100, 1)), columns=list('A'))
bp = df.boxplot(column = 'A')
bp.set_title("This Title")

then I get a box plot with "This Title" as the title, showing up in the plot pane, which is what I want.

However, if I run the above code line by line in the IPython console, the 2nd line will produce a boxplot as expected, but the 3rd line will not have an effect on the image in the plot pane, so the image in the plot pane still do not have a title

Now,if i go to Tools > Preference >IPython Console > Graphics and set the graphics backend to Automatic instead of the default Inline, then when I run the code in the Console line by line, I get an image that pops up in another window, and that it does update/refreshes based on new lines entered into the console. I understand that the inline plots are supposed to be static, but I thought I saw another post where someone said that it is possible to update inline plots? So now my questions are:

  1. Do plots only update/refresh by line codes in the IPython console if the Graphics Backend is not static like inline?
  2. Why do I get different result when I run code blocks vs line by line?
  3. If it is possible to update the inline plots (preferably in the plot pane of Spyder), how do you do it? I've tried various methods to redraw the plots,for example
plt.show()
plt.draw()
bp.get_figure().canvas.draw()

but none of these updates the image in the plot pane. I figured that even if I can't update the image, I should at least be able to redraw it (i.e a 2nd image appears in the plot pane with the update characteristics). But nothing I've tried worked so far. Please advise and thanks again.

Carlos Cordoba
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wwyws
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1 Answers1

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(Spyder maintainer here) About your questions:

Do plots only update/refresh by line codes in the IPython console if the Graphics Backend is not static like inline?

Correct.

Why do I get different result when I run code blocks vs line by line?

Because when you run code cells (which is what I think you mean by "code blocks") your plot is shown at the end of that code and hence it takes all modifications you've done to it in intermediate lines.

If it is possible to update the inline plots (preferably in the plot pane of Spyder), how do you do it?

No, it's not possible. As you correctly mentioned above, inline plots are static images, so they can't be modified.

Carlos Cordoba
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  • Thank you so much for the response. While it's not possible to update the original inline plot,is there a way to re-draw the inline plot after setting the title? – wwyws Jan 20 '20 at 15:48
  • No, any additional command (like setting the title) generates a new inline plot. – Carlos Cordoba Jan 20 '20 at 16:34
  • That's what I meant - generating a new inline plot. What command do I use, after updating the title, in order to draw a new plot? doing plt.draw() or bp.get_figure().canvas.draw() doesn't even seem to work for me. – wwyws Jan 29 '20 at 02:57
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    There's no command to do that. You need to do everything in a single file or cell run. – Carlos Cordoba Jan 29 '20 at 04:03