An important part of becoming “good” at a language is becoming familiar with its library eco-system.

The official Python Standard Library reference manual rocks.

ModuleCategoryDescription
argparsefunctions for parsing command line arguments
atexitallows you to register functions for your program to call when it exits
bisectbisection algorithms for sorting lists (see Chapter 10)
calendara number of date-related functions
codecsfunctions for encoding and decoding data
collectionsa variety of useful data structures
concurrentasynchronous computation
copyfunctions for copying data
csvfunctions for reading and writing CSV files
datetimeclasses for handling dates and times
fileinputfile accessiterate over lines from multiple files or input streams
fnmatchfunctions for matching Unix-style filename patterns
globfunctions for matching Unix-style path patterns
iofunctions for handling I/O streams and StringIO, which allows you to treat strings as files.
jsonfunctions for reading and writing data in JSON format
loggingaccess to Python’s own built-in logging functionality
multiprocessingallows you to run multiple subprocesses, while providing an API that makes them look like threads
operatorfunctions implementing the basic Python operators, instead of writing your own lambda expressions
osswiss army knifeaccess to basic OS functions
pprintdata typesdata pretty printer
randomfunctions for generating pseudorandom numbers
reregular expression functionality
schedan event scheduler without using multithreading
selectaccess to the select() and poll() functions for creating event loops
shutilfile accessaccess to high-level file functions
signalfunctions for handling POSIX signals
tempfilefile accessfunctions for creating temporary files and directories
threadingaccess to high-level threading functionality
urllibprovides functions for handling and parsing URLs
uuidallows you to generate Universally Unique Identifiers (UUIDs)