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21 Python: pandas plot

  • Python library pandas include several plot options which is integrated with matplotlib
  • You need to run both pandas and matplotlib
  • The following examples provide a glimpse of some plot options

21.2 Python: Read Data

Set the working directory to the data folder and read the iris dataset as an R object DF.

import pandas as pd

import numpy as np

import matplotlib.pyplot as plt

DF = pd.read_csv('iris.csv')

Plots are created using pandas with matplotlib

21.3 Single variable

21.3.1 Histogram 


DF.hist('SepalLength')
array([[<AxesSubplot:title={'center':'SepalLength'}>]], dtype=object)
plt.show()

21.3.2 Density plot 


DF[['SepalLength']].plot.density()
plt.show()

21.3.3 Boxplot 


plt.clf()
DF.boxplot(column = 'SepalLength')
plt.show()
plt.clf()
DF.boxplot()
plt.show()

21.3.4 Bar plot 


plt.clf()
cts = DF['Species'].value_counts()
cts.plot.bar()
# cts.plot.barh()
plt.show()

21.3.5 Pie chart 


plt.clf()
cts = DF['Species'].value_counts()
cts.plot.pie()
plt.show()

21.4 Multiple variables

21.4.1 Scatter plot 


plt.clf()
DF.plot.scatter(x = 'SepalLength', y = 'SepalWidth')
plt.show()

21.4.2 Scatter plot matrix 

plt.clf()
pd.plotting.scatter_matrix(DF.iloc[:, 0:4])
plt.show()
array([[<AxesSubplot:xlabel='SepalLength', ylabel='SepalLength'>,
        <AxesSubplot:xlabel='SepalWidth', ylabel='SepalLength'>,
        <AxesSubplot:xlabel='PetalLength', ylabel='SepalLength'>,
        <AxesSubplot:xlabel='PetalWidth', ylabel='SepalLength'>],
       [<AxesSubplot:xlabel='SepalLength', ylabel='SepalWidth'>,
        <AxesSubplot:xlabel='SepalWidth', ylabel='SepalWidth'>,
        <AxesSubplot:xlabel='PetalLength', ylabel='SepalWidth'>,
        <AxesSubplot:xlabel='PetalWidth', ylabel='SepalWidth'>],
       [<AxesSubplot:xlabel='SepalLength', ylabel='PetalLength'>,
        <AxesSubplot:xlabel='SepalWidth', ylabel='PetalLength'>,
        <AxesSubplot:xlabel='PetalLength', ylabel='PetalLength'>,
        <AxesSubplot:xlabel='PetalWidth', ylabel='PetalLength'>],
       [<AxesSubplot:xlabel='SepalLength', ylabel='PetalWidth'>,
        <AxesSubplot:xlabel='SepalWidth', ylabel='PetalWidth'>,
        <AxesSubplot:xlabel='PetalLength', ylabel='PetalWidth'>,
        <AxesSubplot:xlabel='PetalWidth', ylabel='PetalWidth'>]],
      dtype=object)

21.4.3 Boxplot 


plt.clf()
DF.boxplot(column = 'SepalLength', by = 'Species')
plt.show()
plt.clf()
DF.boxplot(by = 'Species')
plt.show()
array([[<AxesSubplot:title={'center':'PetalLength'}, xlabel='[Species]'>,
        <AxesSubplot:title={'center':'PetalWidth'}, xlabel='[Species]'>],
       [<AxesSubplot:title={'center':'SepalLength'}, xlabel='[Species]'>,
        <AxesSubplot:title={'center':'SepalWidth'}, xlabel='[Species]'>]],
      dtype=object)