How to add a y label for each subplot in matplotlib - python

fig = plt.figure()
ax1 = fig.add_subplot(2,1,1)
ax1.ylabel("raw")
ax2 = fig.add_subplot(2,1,2)
ax2.ylabel("smooth")
ax1.plot(a)
ax2.plot(smoothdata())
plt.show()
I need to be able to add y axis labels to each of the plots, i know how to do it with just one plot by doing plt.ylabel('raw") but how do i do it with multiple plots?

Axes object do not have method ylabel, use set_ylabel

ylabel() would be valid for matplotlib.pyplot. From the docs:
matplotlib.pyplot.ylabel(ylabel, fontdict=None, labelpad=None, **kwargs)
Example:
import matplotlib.pyplot as plt
plt.plot(x, y)
plt.ylabel("Label on plt")
plt.show()
If you have multiple plots (subplots) you must use set_ylabel() on each subplot axes:
import matplotlib.pyplot as plt
fig = plt.figure()
ax1 = fig.add_subplot(2,1,1)
ax1.set_ylabel("raw") ### <---
ax2 = fig.add_subplot(2,1,2)
ax2.set_ylabel("smooth") ### <---
ax1.plot([i for i in range(0, 10)], [i for i in range(0, 10)])
ax2.plot([i for i in range(0, 20)], [i for i in range(0, 20)])
plt.show()
Outputs:

Related

How to share x of one ax with that of the other two using matplotlib?

Here is what I have. Is it possible to align bars in ax1 with the others?
image
import numpy as np
import matplotlib.pyplot as plt
x= np.arange(10)+.5
y = np.sin(x)
fig=plt.figure()
ax1 = plt.subplot(211)
ax2 = plt.subplot(223)
ax3 = plt.subplot(224)
ax1.bar(x,y)
ax2.bar(x[:5],y[:5])
ax3.bar(x[5:],y[5:])
plt.show()

Markers in beginning and end of line plots

I have 5 datasets that have thousands of x and y coordinates grouped by 'frame' that create 5 trajectory plots. I'd like to mark the first and last coordinates for each plot but having difficulty figuring it out. I am using Jupiter Notebook.
mean_pos1 = gr1.mean()
mean_pos2 = gr2.mean()
mean_pos3 = gr3.mean()
mean_pos4 = gr4.mean()
mean_pos5 = gr5.mean()
plt.figure()
xlim=(200, 1500)
ylim=(0, 1200)
ax1 = mean_pos1.plot(x='x', y='y',color='blue',label='Dolphin A'); ax1.set_title('mean trajectory');
ax2 = mean_pos2.plot(x='x', y='y',color='red',label='Dolphin B'); ax2.set_title('mean trajectory');
ax3 = mean_pos3.plot(x='x', y='y',color='green',label='Dolphin C'); ax3.set_title('mean trajectory');
ax4 = mean_pos4.plot(x='x', y='y',color='magenta',label='Dolphin D'); ax4.set_title('mean trajectory');
ax5 = mean_pos5.plot(x='x', y='y',color='cyan',label='Dolphin E'); ax5.set_title('mean trajectory');
ax1.set_xlim(xlim)
ax1.set_ylim(ylim)
ax2.set_xlim(xlim)
ax2.set_ylim(ylim)
ax3.set_xlim(xlim)
ax3.set_ylim(ylim)
ax4.set_xlim(xlim)
ax4.set_ylim(ylim)
ax5.set_xlim(xlim)
ax5.set_ylim(ylim)
plt.show()
the output of them looks like this:
Use the scatter method to plot the markers separately on the same axis by grabbing the first and last elements from your x and y series:
import numpy as np
import matplotlib.pyplot as plt
import pandas as pd
df = pd.DataFrame({'x': np.random.normal(3,0.2,10), 'y': np.random.normal(5,0.3,10)})
fig, ax = plt.subplots()
df.plot(x='x', y='y', ax=ax)
ax.scatter(df['x'].iloc[0], df['y'].iloc[0], marker='o', color='red')
ax.scatter(df['x'].iloc[-1], df['y'].iloc[-1], marker='o', color='red')
plt.show()

Moving a plot between figures in matplotlib [duplicate]

Looking at the matplotlib documentation, it seems the standard way to add an AxesSubplot to a Figure is to use Figure.add_subplot:
from matplotlib import pyplot
fig = pyplot.figure()
ax = fig.add_subplot(1,1,1)
ax.hist( some params .... )
I would like to be able to create AxesSubPlot-like objects independently of the figure, so I can use them in different figures. Something like
fig = pyplot.figure()
histoA = some_axes_subplot_maker.hist( some params ..... )
histoA = some_axes_subplot_maker.hist( some other params ..... )
# make one figure with both plots
fig.add_subaxes(histo1, 211)
fig.add_subaxes(histo1, 212)
fig2 = pyplot.figure()
# make a figure with the first plot only
fig2.add_subaxes(histo1, 111)
Is this possible in matplotlib and if so, how can I do this?
Update: I have not managed to decouple creation of Axes and Figures, but following examples in the answers below, can easily re-use previously created axes in new or olf Figure instances. This can be illustrated with a simple function:
def plot_axes(ax, fig=None, geometry=(1,1,1)):
if fig is None:
fig = plt.figure()
if ax.get_geometry() != geometry :
ax.change_geometry(*geometry)
ax = fig.axes.append(ax)
return fig
Typically, you just pass the axes instance to a function.
For example:
import matplotlib.pyplot as plt
import numpy as np
def main():
x = np.linspace(0, 6 * np.pi, 100)
fig1, (ax1, ax2) = plt.subplots(nrows=2)
plot(x, np.sin(x), ax1)
plot(x, np.random.random(100), ax2)
fig2 = plt.figure()
plot(x, np.cos(x))
plt.show()
def plot(x, y, ax=None):
if ax is None:
ax = plt.gca()
line, = ax.plot(x, y, 'go')
ax.set_ylabel('Yabba dabba do!')
return line
if __name__ == '__main__':
main()
To respond to your question, you could always do something like this:
def subplot(data, fig=None, index=111):
if fig is None:
fig = plt.figure()
ax = fig.add_subplot(index)
ax.plot(data)
Also, you can simply add an axes instance to another figure:
import matplotlib.pyplot as plt
fig1, ax = plt.subplots()
ax.plot(range(10))
fig2 = plt.figure()
fig2.axes.append(ax)
plt.show()
Resizing it to match other subplot "shapes" is also possible, but it's going to quickly become more trouble than it's worth. The approach of just passing around a figure or axes instance (or list of instances) is much simpler for complex cases, in my experience...
The following shows how to "move" an axes from one figure to another. This is the intended functionality of #JoeKington's last example, which in newer matplotlib versions is not working anymore, because axes cannot live in several figures at once.
You would first need to remove the axes from the first figure, then append it to the next figure and give it some position to live in.
import matplotlib.pyplot as plt
fig1, ax = plt.subplots()
ax.plot(range(10))
ax.remove()
fig2 = plt.figure()
ax.figure=fig2
fig2.axes.append(ax)
fig2.add_axes(ax)
dummy = fig2.add_subplot(111)
ax.set_position(dummy.get_position())
dummy.remove()
plt.close(fig1)
plt.show()
For line plots, you can deal with the Line2D objects themselves:
fig1 = pylab.figure()
ax1 = fig1.add_subplot(111)
lines = ax1.plot(scipy.randn(10))
fig2 = pylab.figure()
ax2 = fig2.add_subplot(111)
ax2.add_line(lines[0])
TL;DR based partly on Joe nice answer.
Opt.1: fig.add_subplot()
def fcn_return_plot():
return plt.plot(np.random.random((10,)))
n = 4
fig = plt.figure(figsize=(n*3,2))
#fig, ax = plt.subplots(1, n, sharey=True, figsize=(n*3,2)) # also works
for index in list(range(n)):
fig.add_subplot(1, n, index + 1)
fcn_return_plot()
plt.title(f"plot: {index}", fontsize=20)
Opt.2: pass ax[index] to a function that returns ax[index].plot()
def fcn_return_plot_input_ax(ax=None):
if ax is None:
ax = plt.gca()
return ax.plot(np.random.random((10,)))
n = 4
fig, ax = plt.subplots(1, n, sharey=True, figsize=(n*3,2))
for index in list(range(n)):
fcn_return_plot_input_ax(ax[index])
ax[index].set_title(f"plot: {index}", fontsize=20)
Outputs respect.
Note: Opt.1 plt.title() changed in opt.2 to ax[index].set_title(). Find more Matplotlib Gotchas in Van der Plas book.
To go deeper in the rabbit hole. Extending my previous answer, one could return a whole ax, and not ax.plot() only. E.g.
If dataframe had 100 tests of 20 types (here id):
dfA = pd.DataFrame(np.random.random((100,3)), columns = ['y1', 'y2', 'y3'])
dfB = pd.DataFrame(np.repeat(list(range(20)),5), columns = ['id'])
dfC = dfA.join(dfB)
And the plot function (this is the key of this whole answer):
def plot_feature_each_id(df, feature, id_range=[], ax=None, legend_bool=False):
feature = df[feature]
if not len(id_range): id_range=set(df['id'])
legend_arr = []
for k in id_range:
pass
mask = (df['id'] == k)
ax.plot(feature[mask])
legend_arr.append(f"id: {k}")
if legend_bool: ax.legend(legend_arr)
return ax
We can achieve:
feature_arr = dfC.drop('id',1).columns
id_range= np.random.randint(len(set(dfC.id)), size=(10,))
n = len(feature_arr)
fig, ax = plt.subplots(1, n, figsize=(n*6,4));
for i,k in enumerate(feature_arr):
plot_feature_each_id(dfC, k, np.sort(id_range), ax[i], legend_bool=(i+1==n))
ax[i].set_title(k, fontsize=20)
ax[i].set_xlabel("test nr. (id)", fontsize=20)

With MatPlotLib, how do I apply autoscaled axes from one graph to a separate graph?

So I have a dataset I want to plot. In this case, I want to plot all the data on the same graph, and then graph each point in the set on its own graph, but keep the axis scale/limits the same for each graph.
So what I need to do is find the values of the autoscaled axis limits that were set for the full set of data, and apply those limits to the graph for each individual points.
I am and have been reading the mpl docs to see if theres any kind of function I can use that will return the axis limits values, but I haven't found anything so far.
Im using Python 3.4 with matplotlib
Thanks,
evamvid
Although it is possible to find the limits with
xmin, xmax = ax.get_xlim()
ymin, ymax = ax.get_ylim()
and set them on another axes with
ax2.set_xlim(xmin, xmax)
ax2.set_ylim(ymin, ymax)
it might be easier to use plt.subplots with sharex=True and sharey=True:
import numpy as np
import matplotlib.pyplot as plt
np.random.seed(2015)
N = 5
x, y = np.random.randint(100, size=(2,N))
fig, axs = plt.subplots(nrows=2, ncols=3, sharex=True, sharey=True)
colors = np.linspace(0, 1, N)
axs[0,0].scatter(x,y, s=200, c=colors)
for i, ax in enumerate(axs.ravel()[1:]):
ax.scatter(x[i], y[i], s=200, c=colors[i], vmin=0, vmax=1)
plt.show()
Another option is to pass an axes to sharex and sharey:
ax3 = subplot(313, sharex=ax1, sharey=ax1)
For example,
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.gridspec as gridspec
import itertools as IT
np.random.seed(2015)
N = 6
x, y = np.random.randint(100, size=(2,N))
colors = np.linspace(0, 1, N)
gs = gridspec.GridSpec(4, 2)
ax = plt.subplot(gs[0, :])
ax.scatter(x, y, s=200, c=colors)
for k, coord in enumerate(IT.product(range(1,4), range(2))):
i, j = coord
ax = plt.subplot(gs[i, j], sharex=ax, sharey=ax)
ax.scatter(x[k], y[k], s=200, c=colors[k], vmin=0, vmax=1)
plt.tight_layout()
plt.show()

matplotlib: can I create AxesSubplot objects, then add them to a Figure instance?

Looking at the matplotlib documentation, it seems the standard way to add an AxesSubplot to a Figure is to use Figure.add_subplot:
from matplotlib import pyplot
fig = pyplot.figure()
ax = fig.add_subplot(1,1,1)
ax.hist( some params .... )
I would like to be able to create AxesSubPlot-like objects independently of the figure, so I can use them in different figures. Something like
fig = pyplot.figure()
histoA = some_axes_subplot_maker.hist( some params ..... )
histoA = some_axes_subplot_maker.hist( some other params ..... )
# make one figure with both plots
fig.add_subaxes(histo1, 211)
fig.add_subaxes(histo1, 212)
fig2 = pyplot.figure()
# make a figure with the first plot only
fig2.add_subaxes(histo1, 111)
Is this possible in matplotlib and if so, how can I do this?
Update: I have not managed to decouple creation of Axes and Figures, but following examples in the answers below, can easily re-use previously created axes in new or olf Figure instances. This can be illustrated with a simple function:
def plot_axes(ax, fig=None, geometry=(1,1,1)):
if fig is None:
fig = plt.figure()
if ax.get_geometry() != geometry :
ax.change_geometry(*geometry)
ax = fig.axes.append(ax)
return fig
Typically, you just pass the axes instance to a function.
For example:
import matplotlib.pyplot as plt
import numpy as np
def main():
x = np.linspace(0, 6 * np.pi, 100)
fig1, (ax1, ax2) = plt.subplots(nrows=2)
plot(x, np.sin(x), ax1)
plot(x, np.random.random(100), ax2)
fig2 = plt.figure()
plot(x, np.cos(x))
plt.show()
def plot(x, y, ax=None):
if ax is None:
ax = plt.gca()
line, = ax.plot(x, y, 'go')
ax.set_ylabel('Yabba dabba do!')
return line
if __name__ == '__main__':
main()
To respond to your question, you could always do something like this:
def subplot(data, fig=None, index=111):
if fig is None:
fig = plt.figure()
ax = fig.add_subplot(index)
ax.plot(data)
Also, you can simply add an axes instance to another figure:
import matplotlib.pyplot as plt
fig1, ax = plt.subplots()
ax.plot(range(10))
fig2 = plt.figure()
fig2.axes.append(ax)
plt.show()
Resizing it to match other subplot "shapes" is also possible, but it's going to quickly become more trouble than it's worth. The approach of just passing around a figure or axes instance (or list of instances) is much simpler for complex cases, in my experience...
The following shows how to "move" an axes from one figure to another. This is the intended functionality of #JoeKington's last example, which in newer matplotlib versions is not working anymore, because axes cannot live in several figures at once.
You would first need to remove the axes from the first figure, then append it to the next figure and give it some position to live in.
import matplotlib.pyplot as plt
fig1, ax = plt.subplots()
ax.plot(range(10))
ax.remove()
fig2 = plt.figure()
ax.figure=fig2
fig2.axes.append(ax)
fig2.add_axes(ax)
dummy = fig2.add_subplot(111)
ax.set_position(dummy.get_position())
dummy.remove()
plt.close(fig1)
plt.show()
For line plots, you can deal with the Line2D objects themselves:
fig1 = pylab.figure()
ax1 = fig1.add_subplot(111)
lines = ax1.plot(scipy.randn(10))
fig2 = pylab.figure()
ax2 = fig2.add_subplot(111)
ax2.add_line(lines[0])
TL;DR based partly on Joe nice answer.
Opt.1: fig.add_subplot()
def fcn_return_plot():
return plt.plot(np.random.random((10,)))
n = 4
fig = plt.figure(figsize=(n*3,2))
#fig, ax = plt.subplots(1, n, sharey=True, figsize=(n*3,2)) # also works
for index in list(range(n)):
fig.add_subplot(1, n, index + 1)
fcn_return_plot()
plt.title(f"plot: {index}", fontsize=20)
Opt.2: pass ax[index] to a function that returns ax[index].plot()
def fcn_return_plot_input_ax(ax=None):
if ax is None:
ax = plt.gca()
return ax.plot(np.random.random((10,)))
n = 4
fig, ax = plt.subplots(1, n, sharey=True, figsize=(n*3,2))
for index in list(range(n)):
fcn_return_plot_input_ax(ax[index])
ax[index].set_title(f"plot: {index}", fontsize=20)
Outputs respect.
Note: Opt.1 plt.title() changed in opt.2 to ax[index].set_title(). Find more Matplotlib Gotchas in Van der Plas book.
To go deeper in the rabbit hole. Extending my previous answer, one could return a whole ax, and not ax.plot() only. E.g.
If dataframe had 100 tests of 20 types (here id):
dfA = pd.DataFrame(np.random.random((100,3)), columns = ['y1', 'y2', 'y3'])
dfB = pd.DataFrame(np.repeat(list(range(20)),5), columns = ['id'])
dfC = dfA.join(dfB)
And the plot function (this is the key of this whole answer):
def plot_feature_each_id(df, feature, id_range=[], ax=None, legend_bool=False):
feature = df[feature]
if not len(id_range): id_range=set(df['id'])
legend_arr = []
for k in id_range:
pass
mask = (df['id'] == k)
ax.plot(feature[mask])
legend_arr.append(f"id: {k}")
if legend_bool: ax.legend(legend_arr)
return ax
We can achieve:
feature_arr = dfC.drop('id',1).columns
id_range= np.random.randint(len(set(dfC.id)), size=(10,))
n = len(feature_arr)
fig, ax = plt.subplots(1, n, figsize=(n*6,4));
for i,k in enumerate(feature_arr):
plot_feature_each_id(dfC, k, np.sort(id_range), ax[i], legend_bool=(i+1==n))
ax[i].set_title(k, fontsize=20)
ax[i].set_xlabel("test nr. (id)", fontsize=20)

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