How to Create Dummy Variables in Python

In this article, we will discuss creating dummy variables in Python with Pandas.

A dummy variable is a variable that indicates whether a separate categorical variable takes on a specific value.

We can create dummy variables in python using get_dummies() method.

Syntax: pandas.get_dummies(data, prefix=None, prefix_sep=’_’,)

• data – input data i.e. it includes pandas data frame, list, set, numpy arrays etc.
• prefix – Initial value
• prefix_sep – Data values separation

#required modules 
import pandas as pd 
import numpy as np 

# create dataset 
df = pd.DataFrame({'Height': ['Small', 'Medium', 'Tall', 'Very Tall'], 
		 }) 

# display dataset 
print(df) 

# create dummy variables 
print(pd.get_dummies(df))

Output:

      Height
0      Small
1     Medium
2       Tall
3  Very Tall
   Height_Medium  Height_Small  Height_Tall  Height_Very Tall
0              0             1            0                 0
1              1             0            0                 0
2              0             0            1                 0
3              0             0            0                 1

Now let’s see List arrays to get dummies

#required modules 
import pandas as pd 
import numpy as np 

# create dataset 
l = pd.Series(list('abc'))

# display dataset 
print(l) 

# create dummy variables 
print(pd.get_dummies(l))

Output:

0    a
1    b
2    c
dtype: object
   a  b  c
0  1  0  0
1  0  1  0
2  0  0  1