I'm using inset_axes() to control the placement of my colorbar legend. The label hangs off the plot just a little bit. Is there a way to just nudge it over without having to do bbox_to_anchor()? Some way to do an offset from the loc parameter? I do want to keep it in the lower left.
import pandas as pd
%matplotlib inline
import matplotlib.pyplot as plt
import matplotlib.colors as mcolors
from mpl_toolkits.axes_grid1.inset_locator import inset_axes
set1 = ax2.scatter(df.x, df.y,
edgecolors = 'none',
c = df.recommended_net_preferred_for_analysis_meters,
norm = mcolors.LogNorm(), cmap='jet')
cbaxes = inset_axes(ax2, width="30%", height="3%", loc=3)
plt.colorbar(set1, cax=cbaxes, format = '%1.2f', orientation='horizontal')
cbaxes.xaxis.set_ticks_position("top")
Related
How can I set a default set of colors for plots made with matplotlib? I can set a particular color map like this
import numpy as np
import matplotlib.pyplot as plt
fig=plt.figure(i)
ax=plt.gca()
colormap = plt.get_cmap('jet')
ax.set_color_cycle([colormap(k) for k in np.linspace(0, 1, 10)])
but is there some way to set the same set of colors for all plots, including subplots?
Sure! Either specify axes.color_cycle in your .matplotlibrc file or set it at runtime using matplotlib.rcParams or matplotlib.rc.
As an example of the latter:
import matplotlib.pyplot as plt
import matplotlib as mpl
import numpy as np
# Set the default color cycle
mpl.rcParams['axes.prop_cycle'] = mpl.cycler(color=["r", "k", "c"])
x = np.linspace(0, 20, 100)
fig, axes = plt.subplots(nrows=2)
for i in range(10):
axes[0].plot(x, i * (x - 10)**2)
for i in range(10):
axes[1].plot(x, i * np.cos(x))
plt.show()
Starting from matplotlib 1.5, mpl.rcParams['axes.color_cycle'] is deprecated. You should use axes.prop_cycle:
import matplotlib as mpl
mpl.rcParams['axes.prop_cycle'] = mpl.cycler(color=["r", "#e94cdc", "0.7"])
In the version of 2.1.0, the below works for me, using set_prop_cycle and module cycler
from cycler import cycler
custom_cycler = (cycler(color=['r','b','m','g']))
ax.set_prop_cycle(custom_cycler)
you can add additional line attribute
custom_cycler = (cycler(color=['r','b','m','g']) + cycler(lw=[1,1,1,2]))
'ax' comes from ax=plt.axes() or any axes generator
With a horizontal log-scaled color bar and logged labels along the bottom, is it possible to show the exponentiated (original) values along the top?
So in this example, there should be ticks and labels along the top of the color bar going from mat.min() = 0.058 to mat.max() = 13.396
import matplotlib as mpl
import matplotlib.pyplot as plt
import numpy as np
mat = np.exp(np.random.randn(20, 20))
plt.matshow(mat)
norm = mpl.colors.Normalize(1, np.log(mat.max()))
plt.colorbar(plt.cm.ScalarMappable(norm=norm), orientation="horizontal")
plt.savefig("rand_mat.png", dpi=200)
Here is the best answer for your response. I've customized it based on that. Does this result match the intent of your question? The color bar and the size of the figure are not the same, so I adjusted them.
import matplotlib as mpl
import matplotlib.pyplot as plt
import numpy as np
np.random.seed(20210404)
mat = np.exp(np.random.randn(20, 20))
norm = mpl.colors.Normalize(1, np.log(mat.max()))
fig, (ax, cax) = plt.subplots(nrows=2, gridspec_kw=dict(height_ratios=[15,1],hspace=0.5))
im = ax.matshow(mat)
cbar = plt.colorbar(plt.cm.ScalarMappable(norm=norm), orientation="horizontal", cax=cax)
cax2 = cax.twiny()
cbar.ax.xaxis.set_label_position("bottom")
iticks = np.arange(mat.min(), mat.max(), 2)
cax2.set_xticks(iticks)
ax_pos = ax.get_position()
cax_pos = cbar.ax.get_position()
new_size = [ax_pos.x0, cax_pos.y0, ax_pos.x1 - ax_pos.x0, cax_pos.y1 - cax_pos.y0]
cbar.ax.set_position(new_size)
plt.show()
At the risk of committing a faux pas, I'll answer my own question with the solution that best suits my needs:
cb.ax.secondary_xaxis("top", functions=(np.exp, np.log))
which gives
Full Code
import matplotlib as mpl
import matplotlib.pyplot as plt
import numpy as np
mat = np.exp(np.random.randn(20, 20))
plt.matshow(mat)
norm = mpl.colors.Normalize(np.log(mat.min()), np.log(mat.max()))
cb = plt.colorbar(plt.cm.ScalarMappable(norm=norm), orientation="horizontal")
cb_ax_top = cb.ax.secondary_xaxis("top", functions=(np.exp, np.log))
cb_ax_top.set_xticks([0.1, 0.5, 1, 4, 10, 20])
I'd like to change the spacing of the horizontal grid lines on a seaborn chart, I've tried setting the style with no luck:
seaborn.set_style("whitegrid", {
"ytick.major.size": 0.1,
"ytick.minor.size": 0.05,
'grid.linestyle': '--'
})
bar(range(len(data)),data,alpha=0.5)
plot(avg_line)
The gridlines are set automatically desipite me trying to overide the tick size
Any suggestions? Thanks!
you can set the tick locations explicitly later, and it will draw the grid at those locations.
The neatest way to do this is to use a MultpleLocator from the matplotlib.ticker module.
For example:
import seaborn as sns
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.ticker as ticker
sns.set_style("whitegrid", {'grid.linestyle': '--'})
fig,ax = plt.subplots()
ax.bar(np.arange(0,50,1),np.random.rand(50)*0.016-0.004,alpha=0.5)
ax.yaxis.set_major_locator(ticker.MultipleLocator(0.005))
plt.show()
The OP asked about modifying tick distances in Seaborn.
If you are working in Seaborn and you use a plotting feature that returns an Axes object, then you can work with that just like any other Axes object in matplotlib. For example:
import matplotlib.pyplot as plt
import seaborn as sns
import statsmodels.api as sm
from matplotlib.ticker import MultipleLocator
df = sm.datasets.get_rdataset("Guerry", "HistData").data
ax = sns.scatterplot('Literacy', 'Lottery', data=df)
ax.yaxis.set_major_locator(MultipleLocator(10))
ax.xaxis.set_major_locator(MultipleLocator(10))
plt.show()
Put if you are working with one of the Seaborn processes that involve FacetGrid objects, you will see precious little help on how to modify the tick marks without manually setting them. You have dig out the Axes object from the numpy array inside FacetGrid.axes .
import matplotlib.pyplot as plt
import seaborn as sns
from matplotlib.ticker import MultipleLocator
tips = sns.load_dataset("tips")
g = sns.lmplot(x="total_bill", y="tip", hue="smoker", data=tips, )
g.axes[0][0].yaxis.set_major_locator(MultipleLocator(3))
Note the double subscript required. g is a FacetGrid object, which holds a two-dimensional numpy array of dtype=object, whose entries are matplotlib AxesSubplot objects.
If you are working with a FacetGrid that has multiple axes, then each one will have to be extracted and modified.
I ran the following code to get two plots next to each other (it is a minimal working example that you can copy):
import pandas as pd
import numpy as np
from matplotlib.pylab import plt
comp1 = np.random.normal(0,1,size=200)
values = pd.Series(comp1)
plt.close("all")
f = plt.figure()
plt.show()
sp1 = f.add_subplot(2,2,1)
values.hist(bins=100, alpha=0.5, color="r", normed=True)
sp2 = f.add_subplot(2,2,2)
values.plot(kind="kde")
Unfortunately, I then get the following image:
This is also an interesting layout, but I wanted the figures to be next to each other. What did I do wrong? How can I correct it?
For clarity, I could also use this:
import pandas as pd
import numpy as np
from matplotlib.pylab import plt
comp1 = np.random.normal(0,1,size=200)
values = pd.Series(comp1)
plt.close("all")
fig, axes = plt.subplots(2,2)
plt.show()
axes[0,0].hist(values, bins=100, alpha=0.5, color="r", normed=True) # Until here, it works. You get a half-finished correct image of what I was going for (though it is 2x2 here)
axes[0,1].plot(values, kind="kde") # This does not work
Unfortunately, in this approach axes[0,1] refers to the subplot that has a plot method but does not know kind="kde". Please take into consideration that the in the first version plot is executed on the pandas object, whereas in the second version plot is executed on the subplot, which does not work with the kind="kde" parameter.
use ax= argument to set which subplot object to plot:
import pandas as pd
import numpy as np
from matplotlib.pylab import plt
comp1 = np.random.normal(0,1,size=200)
values = pd.Series(comp1)
plt.close("all")
f = plt.figure()
sp1 = f.add_subplot(2,2,1)
values.hist(bins=100, alpha=0.5, color="r", normed=True, ax=sp1)
sp2 = f.add_subplot(2,2,2)
values.plot(kind="kde", ax=sp2)
Is it possible to change what colors Matplotlib cycles through when it is generating its own colors for a graph's lines? I'm using the pylab module.
from pylab import *
import matplotlib.cm as cm
x=[1,2,3,4]
y=[5,6,7,8]
fig1 = Figure()
plot1 = fig1.add_subplot(311)
plot1.plot(x,y)
plot2 = fig1.add_subplot(312)
plot2.plot(x,y)
plot3 = fig1.add_subplot(313)
plot3.plot(x,y)
Yes, of course. Since it accept many kinds of color definition. It's easy to define your own color map. Here I just get colors from the colormap hot
import pylab as py
import numpy as np
import matplotlib.cm as cm
a = np.arange(0,10)
py.figure()
for i in np.arange(10):
c = cm.hot(i/10.,1)
py.plot(a,i*a,color=c)
py.show()
The colors are extracted from color maps. You can use one of the predefined colormaps, or define your own.
Unfortunately there is no way to use multiple colormaps per figure, you have to do it manually:
import pylab as pl
import matplotlib.cm as cm
xval = pl.arange(0, 20, 0.2)
pl.subplot(311)
pl.plot(xval, pl.sin(xval), c=cm.summer(0))
pl.subplot(312)
pl.plot(xval, pl.cos(xval), c=cm.spring(0))
pl.subplot(313)
pl.plot(xval, pl.arctan(xval), xval, pl.fabs(xval))
pl.show()