i use jupyterlab together with matplotlib widgets. I have ipywidgets installed.
My goal is to choose which y-axis data is displayed in the bottom of the figure.
When i use the interactive tool to see the coordinates i get only the data of the right y-axis displayed. Both would be really nice^^ My minimal code example:
import matplotlib.pyplot as plt
import numpy as np
%matplotlib widgets
x=np.linspace(0,100)
y=x**2
y2=x**3
fig,ax=plt.subplots()
ax2=ax.twinx()
ax.plot(x,y)
ax2.plot(x,y2)
plt.show()
With this example you might ask why not to plot them to the same y-axis but thats why it is a minimal example. I would like to plot data of different units.
To choose which y-axis is used, you can set the zorder property of the axes containing this y-axis to a higher value than that of the other axes (0 is the default):
ax.zorder = 1
However, that will cause this Axes to obscure the other Axes. To counteract this, use
ax.set_facecolor((0, 0, 0, 0))
to make the background color of this Axes transparent.
Alternatively, use the grab_mouse function of the figure canvas:
fig.canvas.grab_mouse(ax)
See here for the (minimal) documentation for grab_mouse.
The reason this works is this:
The coordinate line shown below the figure is obtained by an event callback which ultimately calls matplotlib.Axes.format_coord() on the axes instance returned by the inaxes property of the matplotlib events that are being generated by your mouse movement. This Axes is the one returned by FigureCanvasBase.inaxes() which uses the Axes zorder, and in case of ties, chooses the last Axes created.
However, you can tell the figure canvas that one Axes should receive all mouse events, in which case this Axes is also set as the inaxes property of generated events (see the code).
I have not found a clean way to make the display show data from both Axes. The only solution I have found would be to monkey-patch NavigationToolbar2._mouse_event_to_message (also here) to do what you want.
Related
I am using Seaborn to make lineplots with a band indicating standard deviations. Something just like the second/third plot in the doc below:
https://seaborn.pydata.org/generated/seaborn.lineplot.html?highlight=lineplot#seaborn.lineplot
I am wondering is that possible to set the edgecolor for the error band separately? I can change linestyle of the band through err_kws. But, if I pass "edgecolor" through err_kws, it seems that nothing happens. Is there someway to allow me to get control with the edges?
Thanks!
As djakubosky notes, the color of the line and the error band are coupled together internally in seaborn's lineplot. I suggest that it is cleaner to modify the properties of the artists after the plot has been generated. This is a cleaner alternative than editing the library source code directly (maintenance headaches, etc).
For the example data shown on the sns.lineplot docs, we can update the error band properties as follows:
import seaborn as sns
fmri = sns.load_dataset("fmri")
ax = sns.lineplot(x="timepoint", y="signal", data=fmri)
# by inspection we see that the PolyCollection is the first artist
for child in ax.get_children():
print(type(child))
# and so we can update its properties
ax.get_children()[0].set_color('k')
ax.get_children()[0].set_hatch('//')
It may be more robust to select by property of the artist rather than selecting the first artist (especially if you have already rendered something on the same axes), e.g. along these lines:
from matplotlib.collections import PolyCollection
for child in ax.findobj(PolyCollection):
child.set_color('k')
child.set_hatch('//')
It appears that it isn't really possible to change this color under the current seaborn implementation. This is because they pass the color of the main line explicitly to the error band as ax.fillbetweenx(... color=original_color). After playing around in the past, I found that this color arg seems to supersede the other color arguments such as facecolor and edgecolor, thus it doesn't matter what you put in there in the err_kws. However you could fix it by editing line 810 in site-packages/seaborn/relational.py from:
ax.fill_between(x, low, high, color=line_color, **err_kws)
to
ax.fill_between(x, low, high, **err_kws)
and passing the colors explicitly through err_kws.
I would like to have charts without axis lines, and in general without the overall box of which the two axes are only a symmetrical half. This should work to emphasize values that overlap with the border, and also make things more aesthetic as in some seaborn and ggplot examples out there.
Can this be accomplished?
You could color the axes spines in white, so they are not visible on white background.
For example:
ax.spines['bottom'].set_color('white')
ax.spines['top'].set_color('white')
ax.spines['right'].set_color('white')
ax.spines['left'].set_color('white')
Not sure exactly what you want to achieve, but if you need to get rid of the bounding box in all you figures you can modify default matplotlib parameters (like the seaborn does):
import matplotlib.pyplot as plt
plt.rc('axes.spines', **{'bottom':True, 'left':True, 'right':False, 'top':False})
this will leave only the bottom and left part of the bounding box (you can remove everything by putting False everywhere). In this case you get something like this
Data area is controlled by the Spine class and you can do more with it if you'd like:
spines_api
spines_demo
Plots is simple and powerful but sometimes I would like to have a little bit more control over individual elements of the plot to fine-tune its appearance.
Is it possible to update the plot object of the backend directly?
E.g., for the default pyplot backend, I tried
using Plots
p = plot(sin)
p.o[:axes][1][:xaxis][:set_ticks_position]("top")
but the plot does not change. Calling p.o[:show]() afterwards does not help, either.
In other words: Is there a way to use the PyPlot interface for a plot that was initially created with Plots?
Edit:
The changes to the PyPlot object become visible (also in the gui) when saving the figure:
using Plots
using PyPlot
p = Plots.plot(sin, top_margin=1cm)
gui() # not needed when using the REPL
gca()[:xaxis][:set_ticks_position]("top")
PyPlot.savefig("test.png")
Here, I used p.o[:axes][1] == gca(). One has to set top_margin=1cm because the plot area is not adjusted automatically (for my actual fine-tuning, this doesn't matter).
This also works for subsequent updates as long as only the PyPlot interface is used. E.g., after the following commands, the plot will have a red right border in addition to labels at the top:
gca()[:spines]["right"][:set_color]("red")
PyPlot.savefig("test.png")
However, when a Plots command like plot!(xlabel="foo") is used, all previous changes made with PyPlot are overwritten (which is not suprising).
The remaining question is how to update the gui interactively without having to call PyPlot.savefig explicitly.
No - the plot is a Plots object, not a PyPlot object. In your specific example you can do plot(sin, xmirror = true).
I'm trying to do the same but didn't find a solution to update an existing plot. But here is a partial answer: you can query information from the PyPlot axes object
julia> Plots.plot(sin, 1:4)
julia> Plots.PyPlot.plt[:xlim]()
(1.0,4.0)
julia> Plots.plot(sin, 20:24)
julia> ax = Plots.PyPlot.plt[:xlim]()
(20.0,24.0)
and it gets updated.
I have a set of 7x4 plots arranged in a grid using subplot. I now want to add diagonal axes on top of these.
I know you can superpose axes on top of previously made subplots by setting the background to 'none':
ax = fig.add_subplot(111)
ax.set_axis_bgcolor('none')
But I can't find a rotated axis thing. Currently I'm trying to use a top view 3D axes, but I'm far from a usable solution there.
I'm willing to accept drawing the axis+ticks by hand, if this is the only way possible.
EDIT: using the floating_axis module, I was able to draw rotated (and sheared) axes, but unable to edit the ticks, which is very necessary for what I need. The following snippet demonstrates adding a floating_axis to an existing figure fig. Any manipulation of the axes' ticks fails.
from matplotlib.transforms import Affine2D
import mpl_toolkits.axisartist.floating_axes as floating_axes
trafo = Affine2D().skew_deg(-10,-10).rotate_deg(45)
grid_helper = floating_axes.GridHelperCurveLinear(trafo, extremes=(0, 4, 0, 4))
artistax = floating_axes.FloatingSubplot(fig, 111, grid_helper=grid_helper)
artistax.set_axis_bgcolor('none')
artistax.axis["top"].set_visible(False)
artistax.axis["right"].set_visible(False)
fig.add_subplot(artistax)
I recently found the function subplots, which seems to be a more elegant way of setting up multiple subplots than subplot. However, I don't seem to be able to be able to change the properties of the axes for each subplot.
import matplotlib.pyplot as plt
import matplotlib as mpl
import numpy as npx = np.linspace(0, 20, 100)
fig, axes = plt.subplots(nrows=2)
for i in range(10):
axes[0].plot(x, i * (x - 10)**2)
plt.ylabel('plot 1')
for i in range(10):
axes[1].plot(x, i * np.cos(x))
plt.ylabel('plot 2')
plt.show()
Only the ylabel for the last plot is shown. The same happens for xlabel, xlim and ylim.
I realise that the point of using subplots is to create common layouts of subplots, but if sharex and sharey are set to false, then shouldn't I be able to change some parameters?
One solution would be to use the subplot function instead, but do I need to do this?
Yes you probably want to use the individual subplot instances.
As you've found, plt.ylabel sets the ylabel of the last active plot. To change the parameters of an individual Axes, i.e. subplot, you can use any one of the available methods. To change the ylabel, you can use axes[0].set_ylabel('plot 1').
pyplot, or plt as you've defined it, is a helper module for quickly accessing Axes and Figure methods without needing to store these objects in variables. As the documentation states:
[Pyplot p]rovides a MATLAB-like plotting framework.
You can still use this interface, but you will need to adjust which Axes is the currently active Axes. To do this, pyplot has an axes(h) method, where h is an instance of an Axes. So in you're example, you would call plt.axes(axes[0]) to set the first subplot active, then plt.axes(axes[1]) to set the other.