The Go Cookbook

Maintained by SuperOrbital.

A community built and contributed collection of practical recipes for real world Golang development.

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The Go Cookbook is built with the help of people like yourself. Please support this site and help others by contributing a recipe of your own.

Running & Packaging

Running a One-Off File
Cross Compiling
Building a binary
Running a file via a shebang line
Exploring Go with a REPL
Managing dependencies

Strings

[work in progress] Concatenating Strings
[work in progress] Detecting a Substring
[work in progress] Detecting All Substrings
[work in progress] Accessing Substrings
Processing a String One Word or Character at a Time
Processing a String by Complex Separators and Patterns
Reversing a String by Word or Character
Replacing Parts of a String
Expanding and Compressing Tabs
Expanding Variables in User Input
Interpolating Functions and Expressions Within Strings
Indenting Here Documents
Escaping Characters
Trimming Blanks from the Ends of a String
Controlling Case
Properly Capitalizing a Title
Turning an Array into a Sentence
Parsing Comma-Separated Data

Numbers

[work in progress] Representing Enums in Go
[work in progress] Checking Whether a String Is a Valid Number
Rounding Floating-Point Numbers
Comparing Floating-Point Numbers
Operating on a Series of Integers
Working with Roman Numerals
Generating Random Numbers
Generating Repeatable Random Number Sequences
Making Numbers Even More Random
Generating Biased Random Numbers
Doing Trigonometry in Degrees, Not Radians
Calculating More Trigonometric Functions
Taking Logarithms
Multiplying Matrices
Using Complex Numbers
Converting Binary, Octal, and Hexadecimal Numbers
Putting Commas in Numbers
Printing Correct Plurals

Dates and Times

Finding Today's Date
Converting DMYHMS to Epoch Seconds
Converting Epoch Seconds to DMYHMS
Adding to or Subtracting from a Date
Difference of Two Dates
Day in a Week/Month/Year or Week Number
Parsing Dates and Times from Strings
Printing a Date
High-Resolution Timers
Short Sleeps

Arrays

Specifying a List in Your Program
Printing a List with Commas
Changing Array Size
Implementing a Sparse Array
Iterating Over an Array
Iterating Over an Array by Reference
Extracting Unique Elements from a List
Finding Elements in One Array but Not Another
Computing Union, Intersection, or Difference of Unique Lists
Appending One Array to Another
Reversing an Array
Processing Multiple Elements of an Array
Finding the First List Element That Passes a Test
Finding All Elements in an Array Matching Certain Criteria
Sorting an Array Numerically
Sorting a List by Computable Field
Implementing a Circular List
Randomizing an Array

Maps

Adding an Element to a Map
[work in progress] Testing for the Presence of a Key in a Map
Deleting from a Map
Traversing a Map
Convert a Map into an Array of keys or values
Printing a Map
Mapes with Multiple Values per Key
Inverting a Map
Sorting a Map
Merging Maps
Finding Common or Different Keys in Two Maps

Files

Checking the Existence of a File
Reading and Writing to Files
Expanding Tildes in Filenames
Creating Temporary Files
Storing a File Inside Your Program Text
Storing Multiple Files in the DATA Area
Writing a Unix-Style Filter Program
Modifying a File in Place with a Temporary File
Modifying a File in Place with the -i Switch
Modifying a File in Place Without a Temporary File
Locking a File
Flushing Output
Doing Non-Blocking I/O
Determining the Number of Unread Bytes
Reading from Many Filehandles Without Blocking
Reading an Entire Line Without Blocking
Counting Lines (or Paragraphs or Records) in a File
Processing Every Word in a File
Reading a File Backward by Line or Paragraph
Trailing a Growing File
Picking a Random Line from a File
Randomizing All Lines
Reading a Particular Line in a File
Processing Variable-Length Text Fields
Removing the Last Line of a File
Processing Binary Files
Using Random-Access I/O
Updating a Random-Access File
Reading a String from a Binary File
Reading Fixed-Length Records
Reading Configuration Files
Testing a File for Trustworthiness
Reading or Writing Unicode from a Filehandle
Comparing the Contents of Two Files
Reading and writing JSON files
Reading and writing YAML files

Directories

Getting and Setting Timestamps
Deleting a File
Copying or Moving a File
Recognizing Two Names for the Same File
Processing All Files in a Directory
Globbing, or Getting a List of Filenames Matching a Pattern
Processing All Files in a Directory Recursively
Removing a Directory and Its Contents
Renaming Files
Splitting a Filename into Its Component Parts
Working with Symbolic File Permissions Instead of Octal Values

Goroutines

Systems Programming

Catching signals
Running Child Processes
Processing Command-line Arguments

Sockets

Writing a TCP Client
Writing a TCP Server
Communicating over TCP
Setting Up a UDP Client
Setting Up a UDP Server
Using Unix Domain Sockets
Identifying the Other End of a Socket
Finding Your Own Name and Address
Closing a Socket After Forking
Writing Bidirectional Clients
Forking Servers
Pre-Forking Servers
Non-Forking Servers
Multitasking Server with Threads
Writing a Multitasking Server with POE
Writing a Multihomed Server
Making a Daemon Server
Restarting a Server on Demand
Managing Multiple Streams of Input

Internet Services