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Uncertainty in Multiclass Classification

Dr. Rishabh Pathak
1. What is Uncertainty in Classification? Uncertainty refers to the model’s confidence or doubt in its predictions. Quantifying uncertainty is important to understand how reliable each prediction is. In multiclass classification , uncertainty estimates provide probabilities over multiple classes, reflecting how sure the model is about each possible class. 2. Methods to Estimate Uncertainty in Multiclass Classification Most multiclass classifiers provide methods such as: predict_proba: Returns a probability distribution across all classes. decision_function: Returns scores or margins for each class (sometimes called raw or uncalibrated confidence scores). The probability distribution from predict_proba captures the uncertainty by assigning a probability to each class. 3. Shape and Interpretation of predict_proba in Multiclass Output shape: (n_samples, n_classes) Each row corresponds to the probabilities of ...
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Pandas

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Dr. Rishabh Pathak

pandas are a powerful Python library designed for data wrangling and analysis. It provides easy-to-use data structures and data manipulation tools built on top of NumPy, making it ideal for working with structured data such as tables.

Core Features of pandas:

1.       DataFrame - Tabular Data Structure: The primary data structure in pandas is the DataFrame, which is essentially a table similar to an Excel spreadsheet or a SQL table. It consists of labeled rows and columns, allowing easy indexing, selection, and filtering of data.

2.      Heterogeneous Data Types: Unlike NumPy arrays that require all elements to be of the same type, pandas allow each column in a DataFrame to have its own data type (integer, float, string, datetime, categorical, etc.), making it more flexible in handling real-world, mixed-type data.

3.      Data Loading and Saving: pandas provide robust input/output functionality for a variety of file formats including:

  • CSV (comma-separated values)
  • Excel spreadsheets
  • SQL databases
  • JSON
  • HTML and more

This facilitates easy data ingestion and export for different workflows.

  1. Data Manipulation: With pandas, you can:
  • Filter and subset data using labels or boolean indexing
  • Sort, group, and aggregate data
  • Merge and join datasets similar to SQL operations
  • Handle missing data (fill, drop, interpolate)
  • Apply functions efficiently across rows or columns

These operations make it easier to preprocess and clean data for analysis or machine learning.

  1. Integration with Other Libraries: pandas work closely with NumPy and matplotlib. DataFrames can be directly used as inputs for plotting functions or machine learning models in scikit-learn after conversion.

Example of Creating a DataFrame:

import pandas as pd
# Create a dataset as a dictionary
data = {
'Name': ["John", "Anna", "Peter", "Linda"],
'Location': ["New York", "Paris", "Berlin", "London"],
'Age': [24, 13, 53, 33]
}
 
# Convert the dictionary to a pandas DataFrame
data_pandas = pd.DataFrame(data)
 
# Display the DataFrame (especially useful in Jupyter notebooks)
display(data_pandas)

The resulting DataFrame looks like a structured table with appropriate labels for columns (Name, Location, Age).

Summary

pandas are a foundational library for data analysis in Python. Its DataFrame object allows handling heterogeneous tabular data efficiently and intuitively. With extensive functionality for data loading, manipulation, and cleaning, pandas is indispensable in preparing data for analytics and machine learning.

 

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