Drop Empty Columns in Pandas
Last Updated : 17 Mar, 2025
Cleaning data is an essential step in data analysis. In this guide we will explore different ways to drop empty, null and zero-value columns in a Pandas DataFrame using Python. By the end you'll know how to efficiently clean your dataset using the dropna() and replace() methods.
Understanding dropna()
The dropna() function is a powerful method in Pandas that allows us to remove rows or columns containing missing values (NaN). Depending on the parameters used it can remove rows or columns where at least one value is missing or only those where all values are missing.
Syntax: DataFrameName.dropna(axis=0, how='any', inplace=False)
Parameters:
- axis: axis takes int or string value for rows/columns. Input can be 0 or 1 for Integer and ‘index’ or ‘columns’ for String.
- how: how takes string value of two kinds only (‘any’ or ‘all’). ‘any’ drops the row/column if ANY value is Null and ‘all’ drops only if ALL values are null.
- inplace: It is a boolean which makes the changes in the data frame itself if True.
Create a Sample DataFrame:
This is the sample data frame on which we will use to perform different operations.
Python import numpy as np import pandas as pd df = pd.DataFrame({'FirstName': ['Vipul', 'Ashish', 'Milan'], "Gender": ["", "", ""], "Age": [0, 0, 0]}) df['Department'] = np.nan print(df) Output:
Example 1: Remove All Null Value Columns
This method removes columns where all values are NaN. If a column is completely empty (contains only NaN values) it is unnecessary for analysis and can be removed using dropna(how='all', axis=1).
Python import numpy as np import pandas as pd df = pd.DataFrame({'FirstName': ['Vipul', 'Ashish', 'Milan'], "Gender": ["", "", ""], "Age": [0, 0, 0]}) df['Department'] = np.nan display(df) df.dropna(how='all', axis=1, inplace=True) display(df) Output:
Example 2: Replace Empty Strings with Null and Drop Null Columns
If a column contains empty strings we need to replace them with NaN before dropping the column. Empty strings are not automatically recognized as missing values in Pandas so converting them to NaN ensures they can be handled correctly. After conversion we use dropna(how='all', axis=1) to remove columns that are entirely empty.
Python import numpy as np import pandas as pd df = pd.DataFrame({'FirstName': ['Vipul', 'Ashish', 'Milan'], "Gender": ["", "", ""], "Age": [0, 0, 0]}) df['Department'] = np.nan display(df) nan_value = float("NaN") df.replace("", nan_value, inplace=True) df.dropna(how='all', axis=1, inplace=True) display(df) Output:
Example 3: Replace Zeros with Null and Drop Null Columns
If columns contain only zero values, we convert them to NaN before dropping them.
Python import numpy as np import pandas as pd df = pd.DataFrame({'FirstName': ['Vipul', 'Ashish', 'Milan'], "Gender": ["", "", ""], "Age": [0, 0, 0]}) df['Department'] = np.nan display(df) nan_value = float("NaN") df.replace(0, nan_value, inplace=True) df.dropna(how='all', axis=1, inplace=True) display(df) Output:
Example 4: Replace Both Zeros and Empty Strings with Null and Drop Null Columns
To clean a dataset fully we may need to replace both zeros and empty strings.
Python import numpy as np import pandas as pd df = pd.DataFrame({'FirstName': ['Vipul', 'Ashish', 'Milan'], "Gender": ["", "", ""], "Age": [0, 0, 0]}) df['Department'] = np.nan display(df) nan_value = float("NaN") df.replace(0, nan_value, inplace=True) df.replace("", nan_value, inplace=True) df.dropna(how='all', axis=1, inplace=True) display(df) Output:
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