pandas
Flexible and powerful data analysis / manipulation library for Python, providing labeled data structures similar to R data.frame objects, statistical functions, and much more
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Quick Overview
Pandas is a powerful open-source data manipulation and analysis library for Python. It provides high-performance, easy-to-use data structures and tools for working with structured data, making it an essential tool for data scientists, analysts, and researchers.
Pros
- Fast and efficient data manipulation with DataFrame and Series objects
- Robust data import/export capabilities for various file formats
- Powerful data alignment and merging functions
- Extensive time series functionality and date range generation
Cons
- Steep learning curve for beginners
- Can be memory-intensive for large datasets
- Some operations may be slower compared to specialized libraries
- Documentation can be overwhelming due to the library's extensive functionality
Code Examples
- Creating a DataFrame and basic operations:
import pandas as pd
# Create a DataFrame
df = pd.DataFrame({'A': [1, 2, 3], 'B': [4, 5, 6], 'C': [7, 8, 9]})
# Display the DataFrame
print(df)
# Select a column
print(df['A'])
# Filter rows
print(df[df['A'] > 1])
- Reading data from a CSV file and performing basic analysis:
# Read CSV file
df = pd.read_csv('data.csv')
# Display basic statistics
print(df.describe())
# Group by a column and calculate mean
grouped = df.groupby('category')['value'].mean()
print(grouped)
- Time series operations:
# Create a date range
dates = pd.date_range(start='2023-01-01', end='2023-12-31', freq='D')
# Create a time series
ts = pd.Series(range(len(dates)), index=dates)
# Resample to monthly frequency
monthly = ts.resample('M').mean()
print(monthly)
Getting Started
To get started with Pandas, follow these steps:
-
Install Pandas using pip:
pip install pandas
-
Import Pandas in your Python script:
import pandas as pd
-
Create a simple DataFrame:
df = pd.DataFrame({'Name': ['Alice', 'Bob', 'Charlie'], 'Age': [25, 30, 35], 'City': ['New York', 'San Francisco', 'London']}) print(df)
This will create a basic DataFrame and display it. From here, you can start exploring Pandas' various functions and methods for data manipulation and analysis.
Competitor Comparisons
The fundamental package for scientific computing with Python.
Pros of NumPy
- More efficient for numerical computations and large array operations
- Smaller memory footprint for numerical data
- Faster execution for mathematical operations on arrays
Cons of NumPy
- Less intuitive for data manipulation and analysis tasks
- Limited support for handling missing data
- Fewer built-in functions for data cleaning and preprocessing
Code Comparison
NumPy:
import numpy as np
arr = np.array([1, 2, 3, 4, 5])
mean = np.mean(arr)
Pandas:
import pandas as pd
df = pd.DataFrame({'col': [1, 2, 3, 4, 5]})
mean = df['col'].mean()
NumPy excels in numerical computations and array operations, making it more efficient for mathematical tasks. It has a smaller memory footprint and faster execution for large-scale numerical operations. However, Pandas offers more intuitive data manipulation and analysis capabilities, better support for handling missing data, and a wider range of built-in functions for data cleaning and preprocessing.
The code comparison demonstrates the difference in syntax and approach between NumPy and Pandas for a simple task like calculating the mean of a set of numbers. NumPy uses arrays, while Pandas uses DataFrames, which provide more flexibility for complex data structures and operations.
scikit-learn: machine learning in Python
Pros of scikit-learn
- Comprehensive machine learning library with a wide range of algorithms
- Consistent API design across different models and tools
- Extensive documentation and examples for various use cases
Cons of scikit-learn
- Less suitable for data manipulation and preprocessing tasks
- Limited support for time series analysis and forecasting
- Steeper learning curve for beginners compared to pandas
Code Comparison
pandas:
import pandas as pd
df = pd.read_csv('data.csv')
df['new_column'] = df['column_a'] + df['column_b']
result = df.groupby('category').mean()
scikit-learn:
from sklearn.preprocessing import StandardScaler
from sklearn.model_selection import train_test_split
from sklearn.linear_model import LogisticRegression
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2)
scaler = StandardScaler().fit(X_train)
model = LogisticRegression().fit(scaler.transform(X_train), y_train)
pandas excels in data manipulation and analysis, while scikit-learn focuses on machine learning algorithms and model building. pandas is more suitable for data preprocessing and exploratory data analysis, whereas scikit-learn provides a comprehensive set of tools for building and evaluating machine learning models.
SciPy library main repository
Pros of SciPy
- Broader scope covering various scientific computing domains
- More extensive mathematical and statistical functions
- Better suited for complex numerical computations and scientific simulations
Cons of SciPy
- Steeper learning curve for beginners
- Less focused on data manipulation and analysis compared to Pandas
- Slower development cycle and less frequent updates
Code Comparison
SciPy example:
from scipy import stats
import numpy as np
data = np.random.normal(0, 1, 1000)
ks_statistic, p_value = stats.kstest(data, 'norm')
Pandas example:
import pandas as pd
df = pd.DataFrame({'A': [1, 2, 3], 'B': [4, 5, 6]})
result = df.groupby('A').sum()
SciPy focuses on scientific computations and statistical tests, while Pandas excels at data manipulation and analysis. SciPy's code often involves more complex mathematical operations, whereas Pandas provides intuitive methods for working with structured data.
The interactive graphing library for Python :sparkles: This project now includes Plotly Express!
Pros of Plotly
- Interactive and dynamic visualizations
- Wide range of chart types and customization options
- Supports both Python and JavaScript, enabling web-based dashboards
Cons of Plotly
- Steeper learning curve for beginners
- Slower rendering for large datasets
- Requires internet connection for some features (CDN-based)
Code Comparison
Pandas:
import pandas as pd
import matplotlib.pyplot as plt
df = pd.DataFrame({'x': [1, 2, 3], 'y': [4, 5, 6]})
df.plot(x='x', y='y')
plt.show()
Plotly:
import plotly.express as px
df = px.data.iris()
fig = px.scatter(df, x="sepal_width", y="sepal_length", color="species")
fig.show()
Key Differences
- Pandas focuses on data manipulation and analysis, while Plotly specializes in data visualization
- Pandas uses static plotting libraries like Matplotlib, whereas Plotly creates interactive plots
- Plotly offers more advanced visualization features, but Pandas provides more robust data handling capabilities
Use Cases
- Pandas: Data cleaning, transformation, and basic analysis
- Plotly: Creating interactive dashboards, complex visualizations, and web-based data presentations
Statistical data visualization in Python
Pros of Seaborn
- Specialized for statistical data visualization
- Easier to create complex plots with fewer lines of code
- Aesthetically pleasing default styles and color palettes
Cons of Seaborn
- More limited in scope compared to Pandas' data manipulation capabilities
- Slower performance for large datasets
- Steeper learning curve for customizing plot details
Code Comparison
Seaborn:
import seaborn as sns
import matplotlib.pyplot as plt
sns.scatterplot(x="sepal_length", y="sepal_width", hue="species", data=iris)
plt.show()
Pandas:
import pandas as pd
import matplotlib.pyplot as plt
iris.plot.scatter(x="sepal_length", y="sepal_width", c="species", cmap="viridis")
plt.show()
Seaborn excels in creating statistical visualizations with minimal code, while Pandas offers broader data manipulation capabilities. Seaborn provides more aesthetically pleasing default plots, but Pandas allows for greater flexibility in data handling. Both libraries complement each other well in data analysis workflows, with Pandas often used for data preparation and Seaborn for visualization.
matplotlib: plotting with Python
Pros of Matplotlib
- More specialized for data visualization and plotting
- Offers greater customization and control over plot aesthetics
- Supports a wider range of plot types and styles
Cons of Matplotlib
- Steeper learning curve for beginners
- Requires more code to create basic plots
- Less integrated with data manipulation tasks
Code Comparison
Matplotlib:
import matplotlib.pyplot as plt
x = [1, 2, 3, 4, 5]
y = [2, 4, 6, 8, 10]
plt.plot(x, y)
plt.show()
Pandas:
import pandas as pd
df = pd.DataFrame({'x': [1, 2, 3, 4, 5], 'y': [2, 4, 6, 8, 10]})
df.plot(x='x', y='y')
While both libraries can create plots, Matplotlib offers more fine-grained control over plot elements, whereas Pandas provides a more streamlined approach for quick visualizations of tabular data. Pandas builds on top of Matplotlib for its plotting functionality, making it easier to create basic plots directly from DataFrames. However, for more complex or customized visualizations, Matplotlib's extensive capabilities shine through.
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pandas: powerful Python data analysis toolkit
Testing | |
Package | |
Meta |
What is it?
pandas is a Python package that provides fast, flexible, and expressive data structures designed to make working with "relational" or "labeled" data both easy and intuitive. It aims to be the fundamental high-level building block for doing practical, real world data analysis in Python. Additionally, it has the broader goal of becoming the most powerful and flexible open source data analysis / manipulation tool available in any language. It is already well on its way towards this goal.
Table of Contents
- Main Features
- Where to get it
- Dependencies
- Installation from sources
- License
- Documentation
- Background
- Getting Help
- Discussion and Development
- Contributing to pandas
Main Features
Here are just a few of the things that pandas does well:
- Easy handling of missing data (represented as
NaN
,NA
, orNaT
) in floating point as well as non-floating point data - Size mutability: columns can be inserted and deleted from DataFrame and higher dimensional objects
- Automatic and explicit data alignment: objects can
be explicitly aligned to a set of labels, or the user can simply
ignore the labels and let
Series
,DataFrame
, etc. automatically align the data for you in computations - Powerful, flexible group by functionality to perform split-apply-combine operations on data sets, for both aggregating and transforming data
- Make it easy to convert ragged, differently-indexed data in other Python and NumPy data structures into DataFrame objects
- Intelligent label-based slicing, fancy indexing, and subsetting of large data sets
- Intuitive merging and joining data sets
- Flexible reshaping and pivoting of data sets
- Hierarchical labeling of axes (possible to have multiple labels per tick)
- Robust IO tools for loading data from flat files (CSV and delimited), Excel files, databases, and saving/loading data from the ultrafast HDF5 format
- Time series-specific functionality: date range generation and frequency conversion, moving window statistics, date shifting and lagging
Where to get it
The source code is currently hosted on GitHub at: https://github.com/pandas-dev/pandas
Binary installers for the latest released version are available at the Python Package Index (PyPI) and on Conda.
# conda
conda install -c conda-forge pandas
# or PyPI
pip install pandas
The list of changes to pandas between each release can be found here. For full details, see the commit logs at https://github.com/pandas-dev/pandas.
Dependencies
- NumPy - Adds support for large, multi-dimensional arrays, matrices and high-level mathematical functions to operate on these arrays
- python-dateutil - Provides powerful extensions to the standard datetime module
- pytz - Brings the Olson tz database into Python which allows accurate and cross platform timezone calculations
See the full installation instructions for minimum supported versions of required, recommended and optional dependencies.
Installation from sources
To install pandas from source you need Cython in addition to the normal dependencies above. Cython can be installed from PyPI:
pip install cython
In the pandas
directory (same one where you found this file after
cloning the git repo), execute:
pip install .
or for installing in development mode:
python -m pip install -ve . --no-build-isolation -Ceditable-verbose=true
See the full instructions for installing from source.
License
Documentation
The official documentation is hosted on PyData.org.
Background
Work on pandas
started at AQR (a quantitative hedge fund) in 2008 and
has been under active development since then.
Getting Help
For usage questions, the best place to go to is StackOverflow. Further, general questions and discussions can also take place on the pydata mailing list.
Discussion and Development
Most development discussions take place on GitHub in this repo, via the GitHub issue tracker.
Further, the pandas-dev mailing list can also be used for specialized discussions or design issues, and a Slack channel is available for quick development related questions.
There are also frequent community meetings for project maintainers open to the community as well as monthly new contributor meetings to help support new contributors.
Additional information on the communication channels can be found on the contributor community page.
Contributing to pandas
All contributions, bug reports, bug fixes, documentation improvements, enhancements, and ideas are welcome.
A detailed overview on how to contribute can be found in the contributing guide.
If you are simply looking to start working with the pandas codebase, navigate to the GitHub "issues" tab and start looking through interesting issues. There are a number of issues listed under Docs and good first issue where you could start out.
You can also triage issues which may include reproducing bug reports, or asking for vital information such as version numbers or reproduction instructions. If you would like to start triaging issues, one easy way to get started is to subscribe to pandas on CodeTriage.
Or maybe through using pandas you have an idea of your own or are looking for something in the documentation and thinking âthis can be improvedâ...you can do something about it!
Feel free to ask questions on the mailing list or on Slack.
As contributors and maintainers to this project, you are expected to abide by pandas' code of conduct. More information can be found at: Contributor Code of Conduct
Top Related Projects
The fundamental package for scientific computing with Python.
scikit-learn: machine learning in Python
SciPy library main repository
The interactive graphing library for Python :sparkles: This project now includes Plotly Express!
Statistical data visualization in Python
matplotlib: plotting with Python
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Try Visual Copilot