Learning GO lang

Learn Go Programming - Golang Tutorial for Beginners: https://www.youtube.com/watch?v=YS4e4q9oBaU

Setting up the env

• Download go binary
• As root, tar -C /usr/local -xzf go1.15.3.src.tar.gz
• vim ~/.basrc
  • Add go binary path
    • export GOROOT=/usr/local/go
    • export PATH=$PATH:$GOROOT/bin
  • Add GOLIB for 3rd party libraries
    • Folder will be automatically created, mkdir /home/shubham_choudhary/golib
    • export GOPATH=/home/shubham_choudhary/golib
    • export PATH=$PATH:$GOPATH
    • Check by running: go get github.com/nsf/gocode and check home/shubham_choudhary/golib
  • Adding workspace
    • Add workspace location too
    • export GOPATH=$GOPATH:/LOCATION_OF_WORKSPACE
  • We didn't mess our WORKSPACE folder with 3rd party libraries via this approach

Running go code

• go run src/path/to/code/Main.go
• go build path/to/code/ to package under bin/ folder

Go Features

• Singe binary file o/p
• Can't declare unused vars
• Very strict on operation with different Primitive types

Primitives

• Bool
• Numberic
  • Integers
    • Signed, Unsigned
    • int, int8, int32
  • Floating
  • Complex
• Text String
  • String
    • UTF-8
    • Immutable
    • Can be concatenated with plus (+)
    • Can be converted to []byte
  • Rune
    • UTF-32
    • Alias for int32
    • Special methods normally requires to process

Constants

• Constants
  • Immutable
  • Assigned at compile time, must be present at that time
  • Implicit type conversion works
  • Can be defined in block
• Enurated constants
  • iota starts at 0 in each const block and increment by one

Collections

• Arrays
  • Collection of items with same types
  • Fixed Size
  • call by value & reference
• Slices
  • Backed by array, it also have same type of array
  • a := []int{10, 20, 30}
  • Size & capacity based
  • Always call by refrence
  • a = append(a, 10)
  • a = append(a, 10, 20, 30)
  • a = append(a, b...) // spreador
  • DANGEROUS, a will be changed use loops
    • b = append(a[:2], a[4:]...)
• Make funtion
  • make(type, size), cap becomes size
  • make(type, size, cap)
• Maps
  • ALWAYS Pass by refrence*
  • always return something like 0, check with ok
  • value, ok = myMap["wrongKey"]
• Structs
  • Collection of different types of data
  • Keyed by name
  • Can be passed by value & reference
  • No inheritance, but embedding possible
  • Tags can be fields of struct to provide metadata