Overview of the Standard Library

Introduction #

Common packages

Here we will discuss the general purpose of a number of common packages grouped by function; we will not go into detail about their inner structure.

• unsafe: contains commands to step out of the Go type-safety which is not needed in normal programs. It can be useful when interfacing with C/C++.
• os: gives a platform-independent interface to operating-system functionality. Its design is Unix-like. It hides the differences between various operating systems to give a consistent view of files and other OS-objects.
• os/exec: gives the possibility to run external OS commands and programs.
• syscall: this is the low-level, external package, which provides a primitive interface to the underlying OS’s calls.
• archive/tar and /zip – compress: contains functionality for (de)compressing files.
• fmt: contains functionality for formatted input-output.
• io: provides basic input-output functionality, mostly as a wrapper around os-functions.
• bufio: wraps around io to give buffered input-output functionality.
• path/filepath: contains routines for manipulating filename paths targeted at the OS used.
• flag: contains functionality to work with command-line arguments.
• strings: contains functions for manipulating and processing strings.
• strconv: converts strings to basic data types.
• unicode: contains special functions for Unicode characters.
• regexp: provides sophisticated pattern-searching functionalities for strings.
• bytes: contains functions for the manipulation of byte slices.
• index/suffixarray: contains methods for very fast searching in strings.
• math: contains the basic mathematical constants and functions.
• math/cmplx: methods for manipulating complex numbers.
• math/rand: contains pseudo-random number generators.
• sort: contains functionality for sorting arrays and user-defined collections.
• math/big: contains multi-precision arithmetic methods for working with arbitrarily large integers and rational numbers.
• container: contains sub-packages that implement containers for manipulating collections, for example:
  • list: for working with doubly-linked lists.
  • ring: for working with circular lists.
• time: contains basic functionalities for working with times and dates.
• log: contains functionalities for logging information in a running program. We’ll use it throughout examples in the following chapters.
• encoding/json: implements the functions for reading/decoding as well as writing/encoding data in JSON format.
• encoding/xml: this is a simple XML 1.0 parser for examples of JSON and XML.
• text/template: use this package to make data-driven templates that can generate textual output mixed with data, like HTML.
• net: contains basic functions for working with network data.
• http: contains functionality for parsing HTTP requests/replies, provides an extensible HTTP server and a basic client.
• html: this is a parser for HTML5.
• crypto – encoding – hash - ...: these form a multitude of packages for encrypting and decrypting data.
• runtime: contains operations for interacting with the Go-runtime, such as the garbage collection and goroutines.
• reflect: implements runtime introspection, allowing a program to manipulate variables with arbitrary types.