Python graph x axis frequency control - python

I want to make the x axis of the graph the same as below.
Ignore the color, I just want the x axis frequency to be in increments of 5.

To get the xticks from the first plot just use:
fig, ax = plt.subplots()
ax = df.plot(kind='bar', stacked=True)
xticks = ax.get_xticklabels()
Then apply it to the other plot with
ax2 = df.plot(...)
ax2.set_xticklabels(xticks)

Related

Matplotlib Plot and Colorbar issues

I have the below plot, however, I am struggling with the 3 questions below....
How can I move X-axis labels (1-31) to the top of the plot?
How can I change formating of the color bar from (7000 to 7k etc.)
How can I change the color from gray to another cmap like "Reds"?
Can I change the figure size? plt.figure(figsize=(20,10)) does not work?
data1 = pd.read_csv("a2data/data1.csv")
data2 = pd.read_csv("a2data/data2.csv")
merged_df = pd.concat([data1, data2])
merged_df.set_index(['month', 'day'], inplace=True)
merged_df.sort_index(inplace=True)
merged_df2=merged_df.groupby(['month', 'day']).deaths.mean().unstack('day')
plt.imshow(merged_df2)
plt.xticks(np.arange(merged_df2.shape[1]), merged_df2.columns)
plt.yticks(np.arange(merged_df2.shape[0]), merged_df2.index)
plt.colorbar(orientation="horizontal")
plt.show()
Let's try:
# create a single subplot to access the axis
fig, ax = plt.subplots()
# passing the `cmap` for custom color
plt.imshow(df, cmap='hot', origin='upper')
# draw the colorbar
cb = plt.colorbar(orientation="horizontal")
# extract the ticks on colorbar
ticklabels = cb.get_ticks()
# reformat the ticks
cb.set_ticks(ticklabels)
cb.set_ticklabels([f'{int(x//1000)}K' for x in ticklabels])
# move x ticks to the top
ax.xaxis.tick_top()
plt.show()
Output:
Try this to invert the y axis:
ax = plt.yticks(np.arange(merged_df2.shape[0]), merged_df2.index)
plt.colorbar(orientation="horizontal")
ax.invert_yaxis()
plt.show()
I think for the color, you can find better in the pyplot documentation, https://matplotlib.org/3.3.1/api/_as_gen/matplotlib.pyplot.plot.html#matplotlib.pyplot.plot

Removing overlapping x-axis labels in pyplot

I'm new to python and attempting to chart some time series data. I'm using pyplot to create 3 stacked line charts which have the same x-axis (dates), but a different scale for the y-axes. However, each y-axis, as well as the x-axis for the bottom chart, have overlapping labels. There are labels generated from 0 to 1, as well as axis labels from my data set. How do I turn 'off' the auto-generated 0 to 1 labels on the y-axes and the bottom x-axis?
fig, ax = plt.subplots(3,1,sharex='all', squeeze=False, figsize=(12,8))
ax = fig.add_subplot(3,1,1)
plt.plot(df1['date'], df1['value'])
ax2 = fig.add_subplot(3,1,2)
plt.plot(df2['date'], df2['value'])
ax3 = fig.add_subplot(3,1,3)
plt.plot(df3['date'], df3['value'])
plt.show()
You can see the issue in the below picture. Any help is greatly appreciated!
You have already created subplots with all the axes in the initial assignment
fig, ax = plt.subplots(3,1,sharex='all', squeeze=False, figsize=(12,8))
therefore the following assignements of
ax = fig.add_subplot(3,1,1)
ax2 = fig.add_subplot(3,1,2)
ax3 = fig.add_subplot(3,1,3)
are not only unnecessary, but they seem to overlap the already created subplots (if you change it to add_subplot(2,1,1) you will notice it just starts dividing figure again and overlaying axes on top of each other).
What you want to do, is access the axes created in plt.subplots() call:
fig, ax = plt.subplots(3,1,sharex='all', squeeze=False, figsize=(12,8))
ax[0].plot(df1['date'], df1['value'])
ax[1].plot(df2['date'], df2['value'])
ax[2].plot(df3['date'], df3['value'])
plt.show()
Simulated Output:
Data from seaborn tips dataset

Changing Index of the axis in a Graph in matplotlib

I have written a code which will plot a graph of Time VS Amplitude. Now , I want to change the index which is on the horizontal axis. I want to know how I can do it for a single plot and also for the subplots. I want the range of the horizontal axis to be from 0 to 2*pi.
#the following code was written for plotting
fig, (ax1, ax2 ,ax3) = plt.subplots(3 ,constrained_layout = True)
fig.suptitle('AMPLITUDE MODULATION' ,color = 'Red')
ax1.plot(message_signal)
ax1.set_title('Message Signal' ,color = 'green')
I expect the x-axis to go from 0 to 2*pi only. In short, I want to customize the indexing of the x-axis
You can use xlim to set the limits of the x-axis for whole plot or specific axes, e.g. plt.xlim(0, 1) or ax1.set_xlim(0, 1).
Here I set the limits for the x-axis to be [0, 3*pi]
fig, (ax1, ax2 ,ax3) = plt.subplots(3, constrained_layout = True)
fig.suptitle('AMPLITUDE MODULATION', color = 'Red')
x = np.linspace(0, 2*np.pi, 1000)
ax1.plot(x, np.sin(x))
ax1.set_title('Message Signal', color = 'green')
ax1.set_xlim(0, 3*np.pi)

How to align logarithmic scale ticks across subplots?

I want to fix the position of the ticks on the logarithmic scale, such that they are the same in each subplot (see red annotation in image).
My code looks like this:
ax = fig.add_subplot(2,2, axis)
ax2 = ax.twinx()
ax2.set_yscale('log')
ax2.set_ylim(0,100)
Right now, set_yscale=('log') optimizes the tick spacing for each subplot. I prefer to adopt the tick spacing of the upper right subplot.
You can achieve this by getting the limits of the left twin axis and setting it as the limits of the right twin axis.
Consider the following working example. Follow this procedure for the subplots you want to align the axes of.
import numpy as np
import matplotlib.pyplot as plt
fig = plt.figure(figsize=(8, 3))
axl = fig.add_subplot(121)
axr = fig.add_subplot(122)
ax1 = axl.twinx()
ax1.plot(np.logspace(-2, 3, 5))
ax1.set_yscale('log')
ax2 = axr.twinx()
ax2.plot(np.logspace(0, 3, 5))
ax2.set_yscale('log')
ax2.set_ylim(ax1.get_ylim()) # <-- This is the key line
plt.tight_layout()
plt.show()
OP's solution:
Plot a dummy curve and set alpha=0. Make sure the curve spans y_min and y_max.
fig = plt.figure()
axes = [1,2,3,4]
for axis in axes:
ax = fig.add_subplot(2,2, axis)
ax2 = ax.twinx()
ax2.set_yscale('log')
ax2.plot(x_dummy, y_dummy, alpha=0) # <-- dummy plot
x_real, y_real = func_that_loads_data() # <-- your interesting plot
curve1 = ax2.plot(x_real, y_real)
plt.show()
The solution provided by Sheldore was impractical to implement because I plot my data using a for-loop (unavoidable unless I escalate the number of variables).
Since I overwrite the ax variable on every iteration, I would have to save the y-limit as a global variable. Read here why global variables should be avoided.
ax = fig.add_subplot(2,2, axis)
ax2 = ax.twinx()
ax2.set_yscale('log')
if axis == 1:
global yscale
yscale = ax2.get_ylim() # <-- where the magic happens
elif axis > 1:
ax2.set_ylim(yscale)

get the tick labels from a plot and use for another plot

I am trying to get the values of xticks from one plot and then use these values for another plot but set the new ticks as 10 to the power of the other plot's ticks. The following lines doesn't do the job I am aiming for
labels=[item for item in ax1.get_xticklabels()]
ax2.set_xticklabels(['$10^{{{:d}}}$'.format(int(i)) for i in labels])
I will appreciate for any suggestion.
What about sharing axes ? This will fix the same limits and number of ticks for ax1 and ax2 :
fig, ax = plt.subplots(1, 2, sharex=True)
ax1 = ax[0]
ax2 = ax[1]
Then your code will do the trick since you are sure that both subplots have the same xticks
labels = [item for item in ax2.get_xticklabels()]
ax2.set_xticklabels(['$10^{{{:d}}}$'.format(int(i)) for i in labels])

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