Introduction to pandas DataFrame min() Method

Understanding the Basics

The min() method in pandas can be utilized to calculate the minimum values across the rows or columns of a DataFrame. Here’s the basic syntax:

codeDataFrame.min(axis=0, skipna=True, level=None, numeric_only=None, **kwargs) 

• axis : Determines whether to compute the minimum across rows or columns. 0 or 'index' calculates it column-wise, and 1 or 'columns' calculates it row-wise.
• skipna : If set to True , it will skip NaN values while computing the minimum. If False , it will return NaN for columns with NaN values.
• level : In case the DataFrame has MultiIndex, this parameter specifies the level over which to compute the minimum.
• numeric_only : When set to True , it considers only numeric data types for the operation.

Examples and Use Cases

Calculating Minimum Values Column-wise

codeimport pandas as pd 
    
data = { 
    'A': [1, 2, 3, 4], 
    'B': [5, 6, None, 8], 
    'C': [9, 10, 11, 12] 
} 

df = pd.DataFrame(data) 
min_values = df.min() 
print(min_values) 

Output:

codeA 1.0 
B 5.0 
C 9.0 
dtype: float64 

In this example, the min() method calculates the minimum value for each column.

Calculating Minimum Values Row-wise

To calculate row-wise, set axis=1 .

codemin_values_row = df.min(axis=1) 
print(min_values_row) 

Output:

code0 1.0 
1 2.0 
2 3.0 
3 4.0 
dtype: float64 

Handling Missing Values

The skipna parameter is crucial when your DataFrame contains missing values.

codemin_values_skipna = df.min(skipna=False) 
print(min_values_skipna) 

Output:

codeA 1.0 
B NaN 
C 9.0 
dtype: float64 

Since skipna is set to False , the minimum value for column 'B' is NaN .

Tips and Tricks

• Always ensure that your DataFrame doesn’t have unexpected missing values. If it does, handle them appropriately before applying the min() method to avoid skewed results.
• For DataFrames with mixed data types, use the numeric_only=True parameter to focus solely on the numeric data types.

Conclusion

The min() method is a powerful and flexible tool for calculating minimum values across DataFrames in pandas. Whether you’re working on exploratory data analysis or preparing your data for machine learning models, understanding how to leverage this function is crucial for efficient data manipulation. With the examples and insights provided in this guide, you’re now well-equipped to apply the min() method in your pandas adventures!