As shown in the figure,
How can I plot a line that have different colors based on a specific value of x ?
The simplest solution here may be to slice your data at the corresponding index of x_lim found by np.where :
from matplotlib import pyplot as plt
import numpy as np
x = np.linspace(0,2*np.pi,100)
y = np.cos(x)*np.exp(-x/2)
# specify your x limitation
x_lim = np.pi
# find the first corresponding idx where the condition x>=x_lim hold
x_lim_idx = np.where(x>=x_lim)[0][0]
# plot sliced data
plt.plot(x[:x_lim_idx],y[:x_lim_idx],'r')
plt.plot(x[x_lim_idx:],y[x_lim_idx:],'b')
which gives for x_lim = np.pi :
And if the remaining gap between the lines bothers you, for small x discretization for instance, you can still close it by making the two slices overlap.
Related
I want to plot from pd df using sns barplot. Everything works fine :
code associated :
result = df.groupby(['Code departement']).size().sort_values(ascending=False)
x=result.index
y=result.values
plot=sns.barplot(x, y)
plot.set(xlabel='Code departement', ylabel='Nombre de transactions')
sns.barplot(x, y, data=df).set_title('title')
But as you can see in PLOT 1, there are too many bars so I just want the 10 highest, and when I slice x and y :
x=result[:10].index
y=result[:10].values
plot=sns.barplot(x, y)
It prints bars unordered like this :
I checked by printing x and y (sliced) and they are right ordered, Idk what I am missing thank you for your help
You didn't state the version you are using, but probably it isn't the latest. Seaborn as well as matplotlib receive quite some improvements with each new version.
With seaborn 0.11.1 you'd get a warning, as x and y is preferred to be passed via keywords, i.e. sns.barplot(x=x, y=y). The warning tries to avoid confusion with the data= keyword. Apart from that, the numeric x-values would appear sorted numerically.
The order can be controlled via the order= keyword. In this case, sns.barplot(x=x, y=y, order=x). To only have the 10 highest, you can pass sns.barplot(x=x, y=y, order=x[:10]).
Also note that you are creating the bar plot twice (just to change the title?), which can be very confusing. As sns.barplot returns the ax (the subplot onto which the plot has been drawn), the usual approach is ax = sns.barplot(...) and then ax.set_title(...). (The name ax is preferred, to easier understand how matplotlib and seaborn example code can be employed in new code.)
The following example code has been tested with seaborn 0.11.1:
import matplotlib.pyplot as plt
import seaborn as sns
import pandas as pd
import numpy as np
print(sns.__version__)
df = pd.DataFrame({'Code departement': np.random.randint(1, 51, 1000)})
result = df.groupby(['Code departement']).size().sort_values(ascending=False)
x = result.index
y = result.values
ax = sns.barplot(x, y, order=x[:10])
ax.set(xlabel='Code departement', ylabel='Nombre de transactions')
ax.set_title('title')
plt.show()
I generate plots like below:
from pylab import *
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.ticker
import matplotlib.ticker as ticker
rcParams['axes.linewidth'] = 2 # set the value globally
rcParams['font.size'] = 16# set the value globally
rcParams['font.family'] = ['DejaVu Sans']
rcParams['mathtext.fontset'] = 'stix'
rcParams['legend.fontsize'] = 24
rcParams['axes.prop_cycle'] = cycler(color=['grey','b','g','r','orange'])
rc('lines', linewidth=2, linestyle='-',marker='o')
rcParams['axes.xmargin'] = 0
rcParams['axes.ymargin'] = 0
t = arange(0,21,1)
v = 2.0
s = v*t
plt.figure(figsize=(12, 4))
plt.plot(t,s,label='$s=%1.1f\cdot t$'%v)
plt.title('Wykres drogi w czasie $s=v\cdot t$')
plt.xlabel('Czas $t$, s')
plt.ylabel('Droga $s$, m')
plt.autoscale(enable=True, axis='both', tight=None)
legend(loc='best')
plt.xlim(min(t),max(t))
plt.ylim(min(s),max(s))
plt.grid()
plt.show()
When I am changing the value t = arange(0,21,1) for example to t = arange(0,20,1) which gives me for example on the x axis max value= 19.0 my max value dispirs from the x axis. The same situation is of course with y axis.
My question is how to force matplotlib to produce always plots where on the axes are max values just at the end of the axes like should be always for my purposes or should be possible to chose like an option?
Imiage from my program in Fortan I did some years ago
Matplotlib is more efficiens that I use it but there should be an opition like that (the picture above).
In this way I can always observe max min in text windows or do take addiional steps to make sure about max min values. I would like to read them from axes and the question is ...Are there such possibilites in mathplotlib ??? If not I will close the post.
Axes I am thinking about more or less
I see two ways to solve the problem.
Set the axes automatic limit mode to round numbers
In the rcParams you can do this with
rcParams['axes.autolimit_mode'] = 'round_numbers'
And turn off the manual axes limits with min and max
plt.xlim(min(t),max(t))
plt.ylim(min(s),max(s))
This will produce the image below. Still, the extreme values of the axes are shown at the nearest "round numbers", but the user can approximately catch the data range limits. If you need the exact value to be displayed, you can see the second solution which cannot be directly used from the rcParams.
or – Manually generate axes ticks
This solution implies explicitly asking for a given number of ticks. I guess there is a way to automatize it depending on the axes size etc. But if you are dealing with more or less every time the same graph size, you can decide a fixed number of ticks manually. This can be done with
plt.xlim(min(t),max(t))
plt.ylim(min(s),max(s))
plt.xticks(np.linspace(t.min(), t.max(), 7)) # arbitrary chosen
plt.yticks(np.linspace(s.min(), s.max(), 5)) # arbitrary chosen
generated the image below, quite similar to your image example.
I'm trying to visualize what filters are learning in CNN text classification model. To do this, I extracted feature maps of text samples right after the convolutional layer, and for size 3 filter, I got an (filter_num)*(length_of_sentences) sized tensor.
df = pd.DataFrame(-np.random.randn(50,50), index = range(50), columns= range(50))
g= sns.clustermap(df,row_cluster=True,col_cluster=False)
plt.setp(g.ax_heatmap.yaxis.get_majorticklabels(), rotation=0) # ytick rotate
g.cax.remove() # remove colorbar
plt.show()
This code results in :
Where I can't see all the ticks in the y-axis. This is necessary
because I need to see which filters learn which information. Is there
any way to properly exhibit all the ticks in the y-axis?
kwargs from sns.clustermap get passed on to sns.heatmap, which has an option yticklabels, whose documentation states (emphasis mine):
If True, plot the column names of the dataframe. If False, don’t plot the column names. If list-like, plot these alternate labels as the xticklabels. If an integer, use the column names but plot only every n label. If “auto”, try to densely plot non-overlapping labels.
Here, the easiest option is to set it to an integer, so it will plot every n labels. We want every label, so we want to set it to 1, i.e.:
g = sns.clustermap(df, row_cluster=True, col_cluster=False, yticklabels=1)
In your complete example:
import matplotlib.pyplot as plt
import seaborn as sns
import pandas as pd
import numpy as np
df = pd.DataFrame(-np.random.randn(50,50), index=range(50), columns=range(50))
g = sns.clustermap(df, row_cluster=True, col_cluster=False, yticklabels=1)
plt.setp(g.ax_heatmap.yaxis.get_majorticklabels(), rotation=0) # ytick rotate
g.cax.remove() # remove colorbar
plt.show()
I seem to have got stuck at a relatively simple problem but couldn't fix it after searching for last hour and after lot of experimenting.
I have two numpy arrays x and y and I am using seaborn's jointplot to plot them:
sns.jointplot(x, y)
Now I want to label the xaxis and yaxis as "X-axis label" and "Y-axis label" respectively. If I use plt.xlabel, the labels goes to the marginal distribution. How can I make them appear on the joint axes?
sns.jointplot returns a JointGrid object, which gives you access to the matplotlib axes and you can then manipulate from there.
import seaborn as sns
import numpy as np
# example data
X = np.random.randn(1000,)
Y = 0.2 * np.random.randn(1000) + 0.5
h = sns.jointplot(X, Y)
# JointGrid has a convenience function
h.set_axis_labels('x', 'y', fontsize=16)
# or set labels via the axes objects
h.ax_joint.set_xlabel('new x label', fontweight='bold')
# also possible to manipulate the histogram plots this way, e.g.
h.ax_marg_y.grid('on') # with ugly consequences...
# labels appear outside of plot area, so auto-adjust
h.figure.tight_layout()
(The problem with your attempt is that functions such as plt.xlabel("text") operate on the current axis, which is not the central one in sns.jointplot; but the object-oriented interface is more specific as to what it will operate on).
Note that the last command uses the figure attribute of the JointGrid. The initial version of this answer used the simpler - but not object-oriented - approach via the matplotlib.pyplot interface.
To use the pyplot interface:
import matplotlib.pyplot as plt
plt.tight_layout()
Alternatively, you can specify the axes labels in a pandas DataFrame in the call to jointplot.
import pandas as pd
import seaborn as sns
x = ...
y = ...
data = pd.DataFrame({
'X-axis label': x,
'Y-axis label': y,
})
sns.jointplot(x='X-axis label', y='Y-axis label', data=data)
Here is the code I'm running:
import pandas as pd
import numpy as np
import seaborn as sns
import matplotlib.pyplot as plt
titanic = sns.load_dataset("titanic")
y =titanic.groupby([titanic.fare//1,'sex']).survived.mean().reset_index() #grouping by 'fare' rounded to an integer and 'sex' and then getting the survivability
x =pd.cut(y.fare, (0,17,35,70,300,515)) #I'm not sure if my format is correct but this is how I cut up the fare values
y['Fare_bins']= x # adding the newly created bins to a new column "Fare_bins' in original dataframe.
#graphing with seaborn
sns.set(style="whitegrid")
g = sns.factorplot(x='Fare_bins', y= 'survived', col = 'sex', kind ='bar' ,data= y,
size=4, aspect =2.5 , palette="muted")
g.despine(left=True)
g.set_ylabels("Survival Probability")
g.set_xlabels('Fare')
plt.show()
The problem I'm having is that Fare_values are showing up as (0,17].
The left side is a circle bracket and the right side is square bracket.
If possible I would like to have something like this:
(0-17) or [0-17]
Next, there seems to be a gap between each bar plot. I was expecting them to be adjoined. There are two graphs being represented, so I don't expect of the bars to be ajoined, but the first 5 bars(first graph)should be connected and the last 5 bars to eachother(second graph).
How can I go about fixing these two issues?
It seems I can add labels.
Just by adding labels to the "cut" method parameters, I can display the Fare_values as I want.
x =pd.cut(y.fare, (0,17,35,70,300,515), labels = ('(0-17)', '(17-35)', '(35-70)', '(70-300)','(300-515)') )
As for the brackets showing around the fare_value groups,
according to the documentation:
right : bool, optional
Indicates whether the bins include the rightmost edge or not. If right == True (the default), then the bins [1,2,3,4] indicate (1,2], (2,3], (3,4].
Still not sure if it's possible to join the bars though.