Discover 140+ Must‑Know Python Libraries for Data Science & AI

Guide: The Python data toolbox covers common libraries, functions, and external tools used throughout the data acquisition to visualization pipeline, including built‑in functions, standard libraries, third‑party packages, and external utilities.

01 File I/O

abs(x) – Built‑in function that returns the absolute value of x. Rating: ★★★

open(name[, mode[, buffering]]) – Built‑in function for default file reading and writing. Rating: ★★★

numpy.loadtxt, numpy.load, numpy.fromfile – Third‑party functions for reading text and binary files. Rating: ★★★

pandas.read_* – Third‑party functions for reading CSV, Excel, HDF5, SQL, etc. Rating: ★★★

xlrd – Third‑party library for reading Excel files. Rating: ★★

xlwt – Third‑party library for writing Excel files. Rating: ★★

pyexcel‑xl, pyExcelerator, openpyxl – Third‑party libraries for Excel read/write. Rating: ★★–★★★

lxml – Third‑party library for XML/HTML parsing. Rating: ★★★

xml – Standard library for XML object parsing and formatting. Rating: ★★★

bsddb3, bsddb, dbhash, adodb, SQLObject, SQLAlchemy – Various database‑related libraries with ratings from ★★ to ★★★.

02 Web Scraping and Parsing

requests – Third‑party library for HTTP requests. Rating: ★★★

urllib, urllib2 – Standard libraries for URL handling with more features in urllib2. Rating: ★★–★★★

urlparse – Standard library for URL parsing. Rating: ★★★

HTMLParser – Standard library for HTML parsing. Rating: ★★★

Scapy – Third‑party framework for distributed crawling and packet manipulation. Rating: ★★★

Beautiful Soup – Third‑party library for HTML/XML parsing. Rating: ★★★

03 Database Connections

mysql‑connector‑python – Official MySQL driver. Rating: ★★★

pymysql – Third‑party MySQL client. Rating: ★★★

MySQL‑python – Third‑party MySQL client (older). Rating: ★★

cx_Oracle – Oracle client library. Rating: ★★★

psycopg2 – Popular PostgreSQL adapter. Rating: ★★★

redis – Standard library client for Redis. Rating: ★★★

pymongo – Official MongoDB driver. Rating: ★★★

HappyBase – Third‑party HBase client. Rating: ★★★

py2neo – Neo4j driver. Rating: ★★★

cassandra‑driver – Driver for Cassandra and DataStax Enterprise. Rating: ★★★

sqlite3 – Standard library for SQLite. Rating: ★★★

pysqlite2 – Third‑party SQLite 3.x driver. Rating: ★★

bsddb3, bsddb, dbhash – Berkeley DB interfaces. Rating: ★★–★★★

adodb – Third‑party database abstraction library. Rating: ★★★

04 Data Cleaning and Transformation

frozenset([iterable]) – Built‑in immutable set. Rating: ★★★

int(x) – Built‑in conversion to integer. Rating: ★★★

isinstance(object, classinfo) – Checks instance type. Rating: ★★★

len(s) – Returns length of an object. Rating: ★★★

long(x) – (Python 2) Returns a long integer. Rating: ★★★

max(iterable[, key]) – Returns the maximum item. Rating: ★★★

min(iterable[, key]) – Returns the minimum item. Rating: ★★★

range(start, stop[, step]) – Generates a range of integers. Rating: ★★★

raw_input(prompt) – Reads user input as a string (Python 2). Rating: ★★★

round(number[, ndigits]) – Rounds a number. Rating: ★★★

set([iterable]) – Built‑in mutable set. Rating: ★★★

slice(start, stop[, step]) – Returns a slice object. Rating: ★★

sorted(iterable[, cmp[, key[, reverse]]]) – Returns a sorted list. Rating: ★★★

xrange(start, stop[, step]) – (Python 2) Returns an xrange object. Rating: ★★★

string – Standard library for string operations. Rating: ★★★

re – Regular‑expression module. Rating: ★★★

random – Pseudo‑random number generator. Rating: ★★★

os, os.path – Operating‑system interfaces and path utilities. Rating: ★★★

prettytable – Formats tables for console output. Rating: ★★

json – JSON encoder/decoder. Rating: ★★★

base64 – Base64, Base32, Base16 encoding/decoding. Rating: ★★★

05 Data Computation and Statistical Analysis

numpy – Fundamental package for scientific computing. Rating: ★★★

scipy – Library for scientific and engineering calculations. Rating: ★★★

pandas – Data analysis library with DataFrame structure. Rating: ★★★

statsmodels – Statistical modeling and econometrics. Rating: ★★★

abs(x) – Returns absolute value. Rating: ★★★

cmp(x, y) – Comparison function (Python 2). Rating: ★★

float(x) – Converts to float. Rating: ★★★

pow(x, y[, z]) – Power function with optional modulus. Rating: ★★★

sum(iterable[, start]) – Sums items. Rating: ★★★

math – Mathematical functions (sin, cos, log, etc.). Rating: ★★★

cmath – Complex‑number versions of math functions. Rating: ★★

decimal – Decimal floating‑point arithmetic. Rating: ★★

fractions – Rational number arithmetic. Rating: ★★

06 Natural Language Processing and Text Mining

nltk – NLP toolkit with corpora and lexical resources. Rating: ★★★

pattern – Web mining, NLP, and machine‑learning toolkit. Rating: ★★★

gensim – Topic‑modeling and document similarity library. Rating: ★★★

jieba – Chinese word segmentation with multiple modes. Rating: ★★★

SnowNLP – Chinese text processing (sentiment, classification, etc.). Rating: ★★

smallseg – Lightweight DFA‑based Chinese segmenter. Rating: ★★

spaCy – Industrial‑strength NLP library. Rating: ★★★

TextBlob – Simple text processing (POS tagging, sentiment, translation). Rating: ★★

PyNLPI – Collection of NLP tools supporting Chinese and English. Rating: ★★★

synonyms – Chinese synonym library for semantic tasks. Rating: ★★★

07 Image and Video Processing

PIL/Pillow – Image loading, processing, and analysis (Pillow is the actively maintained fork). Rating: ★★

OpenCV – Powerful computer‑vision library with bindings for Python. Rating: ★★★

scikit‑image – Image processing toolbox (filters, segmentation, etc.). Rating: ★★

imageop – Standard library for basic image operations. Rating: ★

colorsys – Color‑space conversion utilities. Rating: ★

imghdr – Detects image file type. Rating: ★

08 Audio Processing

TimeSide – Framework for audio analysis, imaging, transcoding, and streaming. Rating: ★★★

audiolazy – Real‑time audio signal processing library. Rating: ★★

pydub – Manipulates audio files (compression, effects, conversion). Rating: ★★★

audioop – Standard library for basic audio operations. Rating: ★★

tinytag – Reads metadata from many audio formats. Rating: ★★

aifc – Reads/writes AIFF and AIFC files. Rating: ★

sunau – Reads/writes Sun AU files. Rating: ★

wave – Reads/writes WAV files. Rating: ★★

chunk – Reads IFF‑85 chunked files. Rating: ★

sndhdr – Determines sound file type. Rating: ★

ossaudiodev – Access to OSS audio interfaces. Rating: ★★★

09 Data Mining / Machine Learning / Deep Learning

Scikit‑Learn – Comprehensive machine‑learning library (classification, regression, clustering, etc.). Rating: ★★★

TensorFlow – Google’s deep‑learning framework supporting computation graphs. Rating: ★★★

NuPIC – HTM‑based machine‑intelligence platform for anomaly detection and prediction. Rating: ★★★

PyTorch – Facebook’s dynamic‑graph deep‑learning library. Rating: ★★

Orange – Visual programming tool for data mining and machine learning. Rating: ★★★

theano – Mature deep‑learning library with GPU support. Rating: ★★★

keras – High‑level neural‑network API running on TensorFlow or Theano. Rating: ★★

neurolab – Simple neural‑network library with flexible configurations. Rating: ★★

PyLearn2 – Theano‑based deep‑learning library offering high flexibility. Rating: ★★★

OverFeat – Deep‑learning library for image classification and object detection. Rating: ★★

Pyevolve – Genetic‑algorithm framework (also supports genetic programming). Rating: ★★

Caffe2 – Facebook’s large‑scale deployment‑oriented deep‑learning framework, strong in computer vision. Rating: ★★

10 Data Visualization

Matplotlib – 2D plotting library producing publication‑quality figures. Rating: ★★★

pyecharts – Baidu ECharts wrapper offering rich interactive charts. Rating: ★★★

seaborn – Higher‑level API built on Matplotlib for statistical graphics. Rating: ★★★

bokeh – Interactive visualizations for web browsers. Rating: ★★★

Plotly – Online interactive graphing library supporting many chart types. Rating: ★★★

VisPy – High‑performance interactive scientific visualizations. Rating: ★★

PyQtGraph – Fast graphics and GUI library for scientific applications. Rating: ★★

ggplot – Grammar of graphics implementation similar to R’s ggplot2. Rating: ★★★

11 Interactive Learning and Integrated Development

IPython / Jupyter – Enhanced interactive shell and notebook environment. Rating: ★★★

Elpy – Emacs Python development environment. Rating: ★★

PTVS – Python tools for Visual Studio. Rating: ★★

PyCharm – Full‑featured Python IDE with debugging, testing, and VCS integration. Rating: ★★★

LiClipse – Eclipse‑based IDE with PyDev support. Rating: ★★

Spyder – Open‑source IDE focused on scientific computing. Rating: ★★

12 Other Python Collaborative Data‑Work Tools

tesseract‑ocr – Open‑source OCR engine supporting 200+ languages. Rating: ★★★

RPython – Integration library for R. Rating: ★★★

Rpy2 – Interface to R from Python.

matpython – MATLAB integration library. Rating: ★★★

Lunatic Python – Lua integration library. Rating: ★★

PyCall.jl – Julia integration library. Rating: ★★

PySpark – Python API for Apache Spark. Rating: ★★★

dumbo – Early Python wrapper for Hadoop MapReduce. Rating: ★★

dpark – Spark‑like MapReduce framework in Python. Rating: ★★

streamparse – Runs Python code on Apache Storm for real‑time streams. Rating: ★★★