How to Create a Correlation Matrix using Pandas?



How to Create a Correlation Matrix using Pandas?

Correlation is a statistical technique that shows how two variables are related. Pandas dataframe.corr() method is used for creating the correlation matrix. It is used to find the pairwise correlation of all columns in the dataframe. Any na values are automatically excluded. For any non-numeric data type columns in the dataframe it is ignored.
To create correlation matrix using pandas, these steps should be taken:

  1. Obtain the data.
  2. Create the DataFrame using Pandas.
  3. Create correlation matrix using Pandas

Example 1: 

# import pandas
import pandas as pd
# obtaining the data
data = {'A': [45, 37, 42],
        'B': [38, 31, 26],
        'C': [10, 15, 17]
        }
# creation of DataFrame
df = pd.DataFrame(data)
# creation of correlation matrix
corrM = df.corr()
corrM

Output:
pandas-matrix-1

 

Values at the diagonal shows the correlation of a variable with itself, hence diagonal shows the correlation 1.

Example 2: 

import pandas as pd
data = {'A': [45, 37, 42, 50],
        'B': [38, 31, 26, 90],
        'C': [10, 15, 17, 100],
        'D': [60, 99, 23, 56],
        'E': [76, 98, 78, 90]
        }
df = pd.DataFrame(data)
corrM = df.corr()
corrM

Output: 
pandas-matrix-2

Example 3: 

import pandas as pd
# Integer and string values can
# never be correlated.
data = {'A': [45, 37, 42, 50],
        'B': ['R', 'O', 'M', 'Y'],
        }
df = pd.DataFrame(data)
corrM = df.corr()
corrM

Output: 
python-matrix-3

Example 4: 

import pandas as pd
data = {'A': [45, 37, 42, 50],
        'B': ['R', 'O', 'M', 'Y'],
        'C': [56, 67, 68, 60],
              
        }
df = pd.DataFrame(data)
corrM = df.corr()
corrM

Output: 
python-matrix-5

Last Updated on October 19, 2021 by admin

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