Mode:
Duration:
1
Coding works best on desktop or with an external keyboard.
Apply Function Example - Pandas Typing CST Test
Apply Function Example — Pandas Code
Applies a custom function to a DataFrame column.
import pandas as pd
# Sample DataFrame
data = {'Name':['Alice','Bob','Charlie'], 'Age':[25,30,35]}
df = pd.DataFrame(data)
# Apply function to Age column
df['AgeCategory'] = df['Age'].apply(lambda x: 'Adult' if x>=30 else 'Young')
print(df)Pandas Language Guide
Pandas is an open-source Python library that provides high-performance, easy-to-use data structures and data analysis tools for working with structured (tabular, multidimensional, and time-series) data.
Primary Use Cases
- ▸Data cleaning, wrangling, and preprocessing
- ▸Exploratory data analysis (EDA) and statistics
- ▸Time-series analysis and financial data handling
- ▸Merging, joining, and reshaping datasets
- ▸Integration with visualization and ML frameworks
Notable Features
- ▸High-performance data structures (DataFrame, Series)
- ▸Label-based and integer-based indexing
- ▸Handling missing data with ease
- ▸Time-series functionality including date ranges and frequency conversion
- ▸Integration with CSV, Excel, SQL, JSON, and other file formats
Origin & Creator
Pandas was created by Wes McKinney in 2008 while he was at AQR Capital to provide a powerful tool for quantitative analysis and financial data processing in Python.
Industrial Note
Pandas is widely used in finance, data science, analytics, scientific computing, machine learning preprocessing, and any domain that requires structured data analysis.
Quick Explain
- ▸Pandas enables efficient handling, cleaning, transformation, and analysis of datasets.
- ▸It provides flexible data structures like DataFrame and Series for tabular data manipulation.
- ▸Pandas integrates seamlessly with NumPy, Matplotlib, and other data science and machine learning libraries.
Core Features
- ▸DataFrame: 2D labeled data structure
- ▸Series: 1D labeled array
- ▸Indexing, slicing, filtering, and selection
- ▸Aggregation, grouping, and pivoting
- ▸Merging, joining, and concatenation
Learning Path
- ▸Learn Python basics and NumPy arrays
- ▸Understand Series and DataFrame structures
- ▸Practice data cleaning, filtering, and selection
- ▸Explore grouping, pivoting, and time-series operations
- ▸Integrate with visualization and ML workflows
Practical Examples
- ▸Read CSV: pd.read_csv('data.csv')
- ▸Filter rows: df[df['column'] > 10]
- ▸Compute mean: df['column'].mean()
- ▸Merge datasets: pd.merge(df1, df2, on='key')
- ▸Resample time-series: df.resample('M').sum()
Comparisons
- ▸Pandas vs NumPy: high-level tabular vs array operations
- ▸Pandas vs SQL: in-memory analytics vs database queries
- ▸Pandas vs Dask: single-machine vs distributed datasets
- ▸Pandas vs Excel: programmatic vs GUI-driven data analysis
- ▸Pandas vs R data.frame: Python vs R ecosystem
Strengths
- ▸Highly expressive and concise API
- ▸Excellent performance on medium-sized datasets
- ▸Seamless integration with NumPy and SciPy
- ▸Rich ecosystem of data science libraries
- ▸Robust support for missing data and time-series analysis
Limitations
- ▸Not optimized for extremely large datasets (consider Dask or PySpark)
- ▸High memory usage with very large DataFrames
- ▸Single-threaded operations limit parallel processing
- ▸Some complex operations require chaining and careful handling
- ▸Learning curve for multi-index and advanced groupby operations
When NOT to Use
- ▸Extremely large datasets exceeding memory
- ▸Real-time streaming data without batching
- ▸GPU-accelerated numerical computations (use CuDF)
- ▸Highly parallel distributed workloads (use PySpark/Dask)
- ▸Unstructured data like images/audio without preprocessing
Cheat Sheet
- ▸pd.read_csv() = load CSV file
- ▸df.head() = first 5 rows
- ▸df.describe() = summary statistics
- ▸df.groupby('column').sum() = aggregation
- ▸df.merge(df2, on='key') = join datasets
FAQ
- ▸Is Pandas free?
- ▸Yes - open-source under BSD license.
- ▸Which languages are supported?
- ▸Python only.
- ▸Can Pandas handle large datasets?
- ▸Yes, up to memory limits; use Dask for larger datasets.
- ▸Is Pandas suitable for machine learning?
- ▸Yes - primarily for preprocessing and feature engineering.
- ▸Which file formats does Pandas support?
- ▸CSV, Excel, SQL, JSON, HDF5, Parquet, and more.
30-Day Skill Plan
- ▸Week 1: DataFrames, Series, and basic operations
- ▸Week 2: Indexing, slicing, filtering
- ▸Week 3: Aggregations, groupby, pivot tables
- ▸Week 4: Time-series and advanced manipulations
- ▸Week 5: Integration with visualization and ML pipelines
Final Summary
- ▸Pandas is the go-to Python library for structured data analysis.
- ▸Provides powerful, flexible data structures and manipulation tools.
- ▸Supports reading/writing from multiple data sources.
- ▸Ideal for cleaning, transforming, and aggregating datasets.
- ▸Seamlessly integrates with visualization, ML, and statistical libraries.
Project Structure
- ▸main.py / notebook.ipynb - main scripts or notebooks
- ▸data/ - raw and processed datasets
- ▸utils/ - helper functions for data cleaning
- ▸plots/ - saved visualizations
- ▸models/ - ML preprocessing or trained models
Monetization
- ▸Data analytics consulting
- ▸Financial data processing tools
- ▸Business intelligence dashboards
- ▸Preprocessing pipelines for ML products
- ▸ETL solutions for enterprises
Productivity Tips
- ▸Use vectorized operations for speed
- ▸Leverage built-in aggregation and transform methods
- ▸Avoid loops over DataFrame rows
- ▸Document and version datasets
- ▸Use notebooks for exploratory analysis
Basic Concepts
- ▸Series: labeled 1D array
- ▸DataFrame: labeled 2D table with columns and rows
- ▸Index: row and column labels
- ▸NaN: missing data placeholder
- ▸GroupBy: aggregation and splitting of datasets