All gridlines below plot line - with twin x-axis [Matplotlib] - python

I'm using matplotlib to produce a plot where I want to show labels on the right and left y-axis. You will notice by running the code that the grid-lines formed by the right-side y-axis appear on top of the plot line, where the left-side lines appear below. I would like them all to appear below the plot. I've tried zorder and set_axisbelow(True) without success.
Example code below:
import matplotlib.pyplot as plt
import matplotlib as mpl
import numpy as np
t = np.linspace(0,5)
x = np.exp(-t)*np.sin(2*t)
fig, ax1 = plt.subplots()
ax1.plot(t, x)
ax2 = ax1.twinx()
ax2.plot(t, x, alpha=0.0)
ax1.set_xticks([0,1,2])
ax1.set_yticks([0.1, 0.2])
ax2.set_yticks([0.3, 0.4, 0.5])
ax1.grid(True, color='lightgray')
ax2.grid(True, color='lightgray')
for a in [ax1, ax2]:
a.spines["top"].set_visible(False)
a.spines["right"].set_visible(False)
a.spines["left"].set_visible(False)
a.spines["bottom"].set_visible(False)
ax1.set_axisbelow(True)
ax2.set_axisbelow(True)
plt.savefig('fig.pdf')
plt.show()

Related

Seaborn axvspan alterating x-axis

I'm trying to create some scatter plots, with seaborn with a specific area of each plot highlighted in red. However when I add the code for axvspan, it changes the x-axis. This is how the plots look prior to axvspan being applied.
When i apply the line for axvpsan:
fig, (ax0, ax1) = plt.subplots(2,1, figsize=(5,10))
ax0.axvspan("0.4", "0.8", color='red', alpha=0.3, label ='Problem Area')
sns.scatterplot(x='Values_1', y='Values_2', data=df3, color='green', ax=ax0)
sns.scatterplot(x='Values_3', y='Values_4', data=df3, color='green', ax=ax1)
plt.show()
It sends up looking like this:
Ultimately, the red section needs to only cover the data between 0.4 and 0.7, but by altering the x-axis it ends up covering all of it.
Any advice?
The unexpected behavior is resulting from passing the xmin and xmax arguments to matplotlib.pyplot.axvspan as str and not as float.
import matplotlib.pyplot as plt
import seaborn as sns
import numpy as np
import pandas as pd
# generate data
rng = np.random.default_rng(12)
df3 = pd.DataFrame({"Values_2": rng.random(100), "Values_1": np.linspace(0., 0.6, 100)})
fig, ax0 = plt.subplots(1,1, figsize=(6, 4))
ax0.axvspan(0.4, 0.8, color='red', alpha=0.3, label ='Problem Area')
sns.scatterplot(x='Values_1', y='Values_2', data=df3, color='green', ax=ax0)
plt.show()
This gives:

set_markersize not working for right side axis

I'm messing around with some plot styles and ran into a curiosity. I have a plot with twinx() to produce ticks on the right-hand side as well as the left. I want to stagger some ticks, some going farther out that others.
I can add padding to any tick on any axes and push out the text via ax.yaxis.get_major_ticks()[1].set_pad(), but when I try to lengthen the tick via ax.yaxis.get_major_ticks()[1].tick1line.set_markersize(), it works for all axes EXCEPT the right side. Any insight?
Please see the code below. I've tried switching up the axis (ax1, ax2) and index.
import matplotlib.pyplot as plt
import matplotlib as mpl
import numpy as np
t = np.linspace(0,5)
x = np.exp(-t)*np.sin(2*t)
fig, ax1 = plt.subplots()
ax1.plot(t, x, alpha=0.0)
ax2 = ax1.twinx()
ax2.plot(t, x, alpha=1.0)
ax1.set_xticks([0,1,2])
ax1.set_yticks([0.1, 0.2])
ax2.set_yticks([0.3, 0.4, 0.5])
ax2.set_xticks([1,2,3])
ax1.grid(True, color='lightgray')
ax2.grid(True, color='lightgray')
for a in [ax1, ax2]:
a.spines["top"].set_visible(False)
a.spines["right"].set_visible(False)
a.spines["left"].set_visible(False)
a.spines["bottom"].set_visible(False)
ax1.set_axisbelow(True)
ax2.set_axisbelow(True)
ax1.xaxis.get_major_ticks()[1].set_pad(15) #
ax1.xaxis.get_major_ticks()[1].tick1line.set_markersize(15)
ax1.yaxis.get_major_ticks()[1].set_pad(15) #
ax1.yaxis.get_major_ticks()[1].tick1line.set_markersize(15)
ax2.yaxis.get_major_ticks()[1].set_pad(15) #
ax2.yaxis.get_major_ticks()[1].tick1line.set_markersize(15)
plt.savefig('fig.pdf')
plt.show()
You need to use tick2line instead of tick1line, since that's the one referring to the top/right axis, according to the documentation.
Change ax2.yaxis.get_major_ticks()[1].tick1line.set_markersize(15) for:
ax2.yaxis.get_major_ticks()[1].tick2line.set_markersize(15)
Result:

ax.grid overwrites ticks labels when spine is in centre

When using ax.grid() and moving the spines to the middle of the plot, the grid lines go over the axes labels. Any way to stop this and move the axes labels to "front"?
EDIT: It is the ticks labels (the numbers) I'm interested in fixing, not the axis label, which can be easily moved.
EDIT: made the MWE and image match exactly
EDIT: matplotlib version 2.0.0
#!/usr/bin/env python
import matplotlib.pyplot as plt
import numpy as np
fig = plt.figure()
ax = plt.gca()
ax.minorticks_on()
ax.grid(b=True, which='major', color='k', linestyle='-',alpha=1,linewidth=1)
ax.grid(b=True, which='minor', color='k', linestyle='-',alpha=1,linewidth=1)
x = np.linspace(-5,5,100)
y = np.linspace(-5,5,100)
plt.plot(x,y)
plt.yticks([-5,-4,-3,-2,-1,0,1,2,3,4,5])
ax.spines['left'].set_position(('data', 0))
plt.show()

In a matplotlib barplot, how can I make sure very small bars are rendered with an equal width?

I'm creating a bar plot in matplotlib with many, many very narrow bars. Here's some example code:
import matplotlib.pyplot as plt
import numpy as np
x = np.arange(100)
y = np.random.poisson(1, size=100)
fig, ax = plt.subplots(figsize=(8, 1))
ax.bar(x, y, width=1, facecolor='red', edgecolor='white', linewidth=1)
ax.grid(color='white', linewidth=1, linestyle='-')
# some plot aesthetics
for spine in ['right', 'top', 'left']:
ax.spines[spine].set_visible(False)
ax.xaxis.set_ticks_position('bottom')
ax.yaxis.set_ticks_position('none')
ax.yaxis.set_major_locator(plt.MultipleLocator(1))
ax.yaxis.set_major_formatter(plt.NullFormatter())
Notice that due to the finite pixel resolution, the bars vary noticeably in rendered width.
What is the best way to create this plot in matplotlib while ensuring that the rendered result has equal-width bars?

Creating sparklines using matplotlib in python

I am working on matplotlib and created some graphs like bar chart, bubble chart and others.
Can some one please explain with an example what is difference between line graph and sparkline graph and how to draw spark line graphs in python using matplotlib ?
for example with the following code
import matplotlib.pyplot as plt
import numpy as np
x=[1,2,3,4,5]
y=[5,7,2,6,2]
plt.plot(x, y)
plt.show()
the line graph generated is the following:
But I couldn't get what is the difference between a line chart and a spark lien chart for the same data. Please help me understand
A sparkline is the same as a line plot but without axes or coordinates. They can be used to show the "shape" of the data in a compact way.
You can cram several line plots in the same figure just by using subplots and changing properties of the resulting Axes for each subplot:
data = np.cumsum(np.random.rand(1000)-0.5)
data = data - np.mean(data)
fig = plt.figure()
ax1 = fig.add_subplot(411) # nrows, ncols, plot_number, top sparkline
ax1.plot(data, 'b-')
ax1.axhline(c='grey', alpha=0.5)
ax2 = fig.add_subplot(412, sharex=ax1)
ax2.plot(data, 'g-')
ax2.axhline(c='grey', alpha=0.5)
ax3 = fig.add_subplot(413, sharex=ax1)
ax3.plot(data, 'y-')
ax3.axhline(c='grey', alpha=0.5)
ax4 = fig.add_subplot(414, sharex=ax1) # bottom sparkline
ax4.plot(data, 'r-')
ax4.axhline(c='grey', alpha=0.5)
for axes in [ax1, ax2, ax3, ax4]: # remove all borders
plt.setp(axes.get_xticklabels(), visible=False)
plt.setp(axes.get_yticklabels(), visible=False)
plt.setp(axes.get_xticklines(), visible=False)
plt.setp(axes.get_yticklines(), visible=False)
plt.setp(axes.spines.values(), visible=False)
# bottom sparkline
plt.setp(ax4.get_xticklabels(), visible=True)
plt.setp(ax4.get_xticklines(), visible=True)
ax4.xaxis.tick_bottom() # but onlyt the lower x ticks not x ticks at the top
plt.tight_layout()
plt.show()
A sparkline graph is just a regular plot with all the axis removed. quite simple to do with matplotlib:
import matplotlib.pyplot as plt
import numpy as np
# create some random data
x = np.cumsum(np.random.rand(1000)-0.5)
# plot it
fig, ax = plt.subplots(1,1,figsize=(10,3))
plt.plot(x, color='k')
plt.plot(len(x)-1, x[-1], color='r', marker='o')
# remove all the axes
for k,v in ax.spines.items():
v.set_visible(False)
ax.set_xticks([])
ax.set_yticks([])
#show it
plt.show()

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