/go-fundamentals

Learning Go

Primary LanguageGo

go-fundamentals

Golang Gopher

NOTE: for single file use and demo purposes, I have multiple main files because this is not a conventional package. I am aware that a go package can only have one main Func.

Learnings from going through the go-fundamentals course by Nigel Poulton

##Variables

  • Uninitailized variables get a Zero value
  • Package level variables are global
  • Package-level variabes must be declared with var
  • Declare function variables with :=
  • Go supports type inference
  • Go passes arguments by value
  • '&' References a pointer
  • * De-References a pointer
  • Go Passes arguments by VALUE

##Functions

  • Functions make your code concise,re-usable, easy to test & debug
  • all statements within a function is enclosed within {}
  • Params and returns are defined within the func signature
  • The return keyword exits a function
  • Go functions can return multiple values
  • Variadic functions - functions that can have an unknown nu mber of paramters

Conditionals

  • 'If' conditions evaulate a Boolean expression for true or false
  • Curly brance must start on the same line of the if,else if, and else statements
  • No Parentheses around the if condition.
  • Simple initlaization Statements in if blocks. This allows block scoped variables
  • Switch statements have an optional simple statement and an expression to be evaulated.
  • Switches have cases to be evaluated and a default statement at the end
  • A switches case statement has an implicit break statements
  • Switches have a fallthrough keyword to run case blocks underneath it. this is case by case basis meaning that a fallthrough keyword only falls through to the next if block
  • Switch statements can more than one value for a case
  • In Go, it is expected to have an error as the last return from functions and emethods
  • In errors, nil is used to indicate success
  • It is best pratice to check returned err variables

##Loops

  • has one keyword for loops. a "for" loop
  • for with a blank expression = infinite loop
  • boolean expression
  • for...range
  • Pre and Post statements
  • Nested
  • Continue and Break
  • Go has a break to a label feature

##Arrays and Slices

  • Arrays are a numbered list of a single type and has a fixed length
  • Slices are also a numbered list of a single type but can be resized.
  • Slices are built on top of an Array.
  • Slices are references that pass portions of an array.
  • Data is never slices in an array!
  • Slices are left side inclusive. The right side is excluded.
  • an array is sliced with [0:4], you will get the value at index 0,1,2,3 and 3.
  • when appending to a slice, once we hit capacity, the underlying array is doubled. Thus we are doubling the capacity.
  • Refrencing a slice by it's variable name, it will show the entire slice
  • for range loops iterate slices
  • for range returns two values, an index and data
  • Can append() slices to slices with ellippses
  • Use slices instead of an array for flexibility

##Maps

  • Unordered list
  • Similar to slices and pointers
  • Maps are dynamic
  • Maps are references
  • Needs keytype and val type when creating a map.
  • Passed to functions by reference
  • Changes made by functions visible caller
  • Unsafe for concurrency
  • Cheapt to pass around.
  • Specify size for large maps.
  • make(map, size)
  • Can improve peformance

##Structs

  • Go's way of defining Custom data types.
  • Go has no objects,classes, nor inheritance.