Seaborn Tutorial
What is Seaborn?
Seaborn is a Python data visualization library based on matplotlib. It provides a high-level interface for drawing attractive and informative statistical graphics.
Import Seaborn and Dataset
import seaborn as sns
%matplotlib inline
import matplotlib.pyplot as plt # required to change the plot styles
plt.style.use('ggplot')
# import build-in seaborn dataset
tips = sns.load_dataset('tips')
tips.head()
"""
total_bill tip sex smoker day time size
0 16.99 1.01 Female No Sun Dinner 2
1 10.34 1.66 Male No Sun Dinner 3
2 21.01 3.50 Male No Sun Dinner 3
3 23.68 3.31 Male No Sun Dinner 2
4 24.59 3.61 Female No Sun Dinner 4
"""
Distribution Plots
sns.distplot(tips["total_bill"])
# jointplot() allows you to basically match up two distplots for bivariate data.
# With your choice of what kind parameter to compare with:
# "scatter”, “reg”, “resid”, “kde”, “hex”
sns.jointplot(x='total_bill', y='tip', data=tips)
# pairplot will plot pairwise relationships across an entire dataframe
# (for the numerical columns) and supports a color hue argument (for categorical columns).
sns.pairplot(tips, hue='sex')
# Rug and kde on one plot
sns.kdeplot(tips['tip'])
sns.rugplot(tips['tip'])
Categorical Plots
# barplot is a general plot that allows you to aggregate the
# categorical data based off some function, by default the mean:
sns.barplot(x='sex',y='total_bill',data=tips)
# countplot
# This is essentially the same as barplot except the estimator
# is explicitly counting the number of occurrences.
# Which is why we only pass the x value:
sns.countplot(x='sex',data=tips)
boxplot and violinplot
boxplots and violinplots are used to shown the distribution of categorical data. A box plot (or box-and-whisker plot) shows the distribution of quantitative data in a way that facilitates comparisons between variables or across levels of a categorical variable. The box shows the quartiles of the dataset while the whiskers extend to show the rest of the distribution, except for points that are determined to be “outliers” using a method that is a function of the inter-quartile range.
sns.boxplot(x="day", y="total_bill", data=tips,palette='rainbow')
sns.boxplot(x="day", y="total_bill", hue="smoker",data=tips, palette="coolwarm")
sns.violinplot(x="day", y="total_bill", data=tips,palette='rainbow')
sns.violinplot(x="day", y="total_bill", data=tips,hue='sex',palette='Set1')
stripplot and swarmplot
The stripplot will draw a scatterplot where one variable is categorical. A strip plot can be drawn on its own, but it is also a good complement to a box or violin plot in cases where you want to show all observations along with some representation of the underlying distribution.
The swarmplot is similar to stripplot(), but the points are adjusted (only along the categorical axis) so that they don’t overlap. This gives a better representation of the distribution of values, although it does not scale as well to large numbers of observations (both in terms of the ability to show all the points and in terms of the computation needed to arrange them).
sns.stripplot(x="day", y="total_bill", data=tips)
sns.stripplot(x="day", y="total_bill", data=tips,jitter=True,hue='sex',palette='Set1',split=True)
sns.swarmplot(x="day", y="total_bill", data=tips)
Combining Categorical Plots
sns.violinplot(x='day', y='total_bill', data=tips)
sns.swarmplot(x='day', y='total_bill', data=tips, color='black')
Factorplot
factorplot is the most general form of a categorical plot. It can take in a kind parameter to adjust the plot type:
sns.factorplot(x='sex',y='total_bill',data=tips,kind='bar')
Matric Plots
Matrix plots allow you to plot data as color-encoded matrices and can also be used to indicate clusters within the data.
import seaborn as sns
%matplotlib inline
# Import the build-in flights dataset
flights = sns.load_dataset('flights')
flights = sns.load_dataset('flights')
flights.head()
"""
year month passengers
0 1949 January 112
1 1949 February 118
2 1949 March 132
3 1949 April 129
4 1949 May 121
"""
Heatmap
In order for a heatmap to work properly, your data should already be in a matrix form, the sns.heatmap function basically just colors it in for you.
flights.pivot_table(values='passengers',index='month',columns='year')
pvflights = flights.pivot_table(values='passengers',index='month',columns='year')
sns.heatmap(pvflights)
sns.heatmap(pvflights,cmap='magma',linecolor='white',linewidths=1)
Clustermap
The clustermap uses hierarchal clustering to produce a clustered version of the heatmap. For example:
sns.clustermap(pvflights)