Go go-to guide (original) (raw)

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](/golang/default-zero-value/ "Variables declared without an initial value are set to their zero values: 0 or 0.0 for numbers, false for booleans, "" for strings, and nil for interfaces, slices, channels, maps, pointers and functions.")
• 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