How to add Empty Column to Dataframe in Pandas?

In DataFrames, Empty columns are defined and represented with NaN Value(Not a Number value or undefined or unrepresentable value). There are various methods to add Empty Column to Pandas Dataframe in Python.

Method 1: Add Empty Column to Dataframe using the Assignment Operator

We are using the assignment operator to assign empty strings to two newly created columns as “Gender” and “Department” respectively for Pandas Dataframes.

Python3

# import required libraries
import numpy as np
import pandas as pd

# create a Dataframe
Mydataframe = pd.DataFrame({'FirstName': ['Vipul',
                                          'Ashish',
                                          'Milan'],
                            "Age": [21,22,23]})
# show the dataframe
print("\n\n---Original Dataframe---\n",
      Mydataframe)

# add an empty columns
Mydataframe['Gender'] = ''
Mydataframe['Department'] = ''

# show the dataframe
print("---Updated Dataframe---\n",
      Mydataframe)

Output:

Method 2: Add Empty Column to Dataframe using the np.nan 

We are using np.nan values to two newly created columns as “Gender” and “Department” respectively for Pandas Dataframes(table). Numpy library is used to import NaN value and use its functionality.

Python3

# import required libraries
import numpy as np
import pandas as pd

# show the dataframe
print("\n\n---Original Dataframe---\n",
      Mydataframe)

# add an empty columns
Mydataframe['Gender'] = np.nan
Mydataframe['Department'] = np.nan

# show the dataframe
print("---Updated Dataframe---\n",
      Mydataframe)

Output:

Method 3: Add Empty Column to Dataframe using the None 

We are using None values to two newly created columns as “Gender” and “Department” respectively for Pandas Dataframes.

Python3

# import required libraries
import numpy as np
import pandas as pd

# show the dataframe
print("\n\n---Original Dataframe---\n",
      Mydataframe)

# add an empty columns
Mydataframe['Gender'] = None
Mydataframe['Department'] = None

# show the dataframe
print("---Updated Dataframe---\n",
      Mydataframe)

Output:

Method 4: Add Empty Column to Dataframe using Dataframe.reindex().

We created a Dataframe with two columns “First name and “Age” and later used Dataframe.reindex() method to add two new columns “Gender” and ” Roll Number” to the list of columns with NaN values.

Python3

# import pandas library
import pandas as pd

# create a dataframe
Mydataframe = pd.DataFrame({'FirstName': ['Preetika',
                                          'Tanya',
                                          'Akshita'],
                            "Age": [25,21,22]})
# show the dataframe
print("---Original Dataframe---\n",
      Mydataframe)

# add an empty columns
Mydataframe = Mydataframe.reindex(columns = Mydataframe.columns.tolist()
                                  + ['Gender','Roll Number'])

# show the dataframe
print("\n\n---Updated Dataframe---\n",
      Mydataframe)

Output:

Method 5: Add Empty Column to Dataframe using Dataframe.insert()

We are using the Dataframe.insert() method on pandas Dataframes to add an empty column “Roll Number”, here we can also insert the column at any index position we want (as here we placed the value at index location 0).

Python3

# import pandas library
import pandas as pd

# create a dataframe
Mydataframe = pd.DataFrame({'FirstName': ['Rohan',
                                          'Martin',
                                          'Mary'],
                            "Age": [28,39,21]})
# show the dataframe
print("---Original Dataframe---\n",
      Mydataframe)

# add an empty column
Mydataframe.insert(0,'Roll Number','')

# show the dataframe
print("\n\n---Updated Dataframe---\n",
      Mydataframe)

Output: