Go go-to guide

Why Go?

• Why Go? – Key advantages you may have overlooked
• Go vs. Java: 15 main differences

Step-by-step guides

• Go step by step
• Type, value and equality of interfaces
• Create, initialize and compare structs
• Slices/arrays explained: create, index, slice, iterate
• Maps explained: create, add, get, delete
• 5 basic for loop patterns
• 5 switch statement patterns
• Packages explained: declare, import, download, document

Go gotchas

• Assignment to entry in nil map
• Invalid memory address or nil pointer dereference
• Multiple-value in single-value context
• Array won’t change
• See all 27 gotchas

Tutorials

• Go tutorials
• Go beginner’s guide: top 4 resources to get you started
• How to use JSON with Go [best practices]
• Regexp tutorial and cheat sheet
• Java to Go in-depth tutorial

Cheat sheets

• Go string handling overview [cheat sheet]
• Conversions [complete list]
• fmt.Printf formatting tutorial and cheat sheet
• Format a time or date [complete guide]
• Regexp tutorial and cheat sheet
• Bitwise operators [cheat sheet]
• Start a new Go project [standard layout]
• Learn to love your compiler

Code for common tasks

• Go blueprints: code for common tasks
• 2 basic FIFO queue implementations
• 2 basic set implementations
• A basic stack (LIFO) data structure
• Access environment variables
• Access private fields with reflection
• Bitmasks, bitsets and flags
• Check if a number is prime
• Command-line arguments and flags
• Go as a scripting language: lightweight, safe and fast
• Compute absolute value of an int/float
• Compute max of two ints/floats
• 3 simple ways to create an error
• Create a new image
• Format byte size as kilobytes, megabytes, gigabytes, ...
• Generate all permutations
• Hash checksums: MD5, SHA-1, SHA-256
• Hello world HTTP server example
• How to best implement an iterator
• 4 iota enum examples
• Maximum value of an int
• Round float to 2 decimal places
• Round float to integer value
• The 3 ways to sort in Go
• Table-driven unit tests

Concurrent programming

• Concurrent programming
• Goroutines are lightweight threads
• Channels offer synchronized communication
• Select waits on a group of channels
• Data races explained
• How to detect data races
• How to debug deadlocks
• Waiting for goroutines
• Broadcast a signal on a channel
• How to kill a goroutine
• Timer and Ticker: events in the future
• Mutual exclusion lock (mutex)
• 3 rules for efficient parallel computation

Object-oriented programming

• Object-oriented programming without inheritance
• Constructors deconstructed [best practice]
• Methods explained
• Public vs. private
• Pointer vs. value receiver

Functional programming

• Functional programming in Go [case study]
• Function types and values
• Anonymous functions and closures
• How to best implement an iterator

Scripting

• Go as a scripting language: lightweight, safe and fast
• Read a file (stdin) line by line
• Command-line arguments and flags
• Access environment variables

StringsCheat sheet

• Go string handling overview [cheat sheet]
• fmt.Printf formatting tutorial and cheat sheet
• Regexp tutorial and cheat sheet
• Runes and character encoding
• Efficient string concatenation [full guide]
• Escapes and multiline strings
• 3 ways to split a string into a slice
• Convert between byte array/slice and string
• Convert between rune array/slice and string
• Convert between float and string
• Convert between int, int64 and string
• Convert interface to string
• Remove all duplicate whitespace
• 3 ways to trim whitespace (or other characters) from a string
• How to reverse a string by byte or rune

MapsStep-by-step

• Maps explained: create, add, get, delete
• 3 ways to find a key in a map
• Get slices of keys and values from a map
• Sort a map by key or value

Slices and arraysStep-by-step

• Slices/arrays explained: create, index, slice, iterate
• 3 ways to compare slices (arrays)
• How to best clear a slice: empty vs. nil
• 2 ways to delete an element from a slice
• Find element in slice/array with linear or binary search
• Last item in a slice/array

Files

• Read a file (stdin) line by line
• Append text to a file
• Find current working directory
• List all files (recursively) in a directory
• Create a temporary file or directory

Time and date

• Format a time or date [complete guide]
• Time zones
• How to get current timestamp
• Get year, month, day from time
• How to find the day of week
• Days between two dates
• Days in a month
• Measure execution time

Random numbers

• Generate random numbers, characters and slice elements
• Generate a random string (password)
• Generate a unique string (UUID, GUID)
• Shuffle a slice or array
• User-friendly access to crypto/rand

Language basics

• Go beginner’s guide: top 4 resources to get you started
• Packages explained: declare, import, download, document
• Package documentation
• Package initialization and program execution order

Statements

• 4 basic if-else statement patterns
• 5 switch statement patterns
• 5 basic for loop patterns
• 2 patterns for a do-while loop in Go
• 4 basic range loop (for-each) patterns
• Defer a function call (with return value)
• Type assertions and type switches
• Type alias explained

Expressions

• Create, initialize and compare structs
• Pointers explained
• Untyped numeric constants with no limits
• Make slices, maps and channels
• How to append anything (element, slice or string) to a slice
• How to use the copy function
• Default zero values for all Go types
• Operators: complete list
• Conversions [complete list]

Methods and interfaces

• Methods explained
• Type, value and equality of interfaces
• Named return values [best practice]
• Optional parameters, default parameter values and method overloading
• Variadic functions (...T)

Error handling

• Error handling best practice
• 3 simple ways to create an error
• Panics, stack traces and how to recover [best practice]

Bits and pieces

• Blank identifier (underscore)
• Find the type of an object
• Generics (alternatives and workarounds)
• Pick the right one: int vs. int64
• 3 dots in 4 places
• Redeclaring variables

Standard library

• How to use JSON with Go [best practices]  encoding/json
• fmt.Printf formatting tutorial and cheat sheet  fmt
• How to use the io.Reader interface  io
• How to use the io.Writer interface  io
• Create a new image  image
• Write log to file (or /dev/null)  log
• Hello world HTTP server example  net/http
• Regexp tutorial and cheat sheet  regexp
• The 3 ways to sort in Go  sort