Go If & Switch

Links: - 103 Golang Index
- Go - ProgramFlow

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If condition

• It is not necessary to enclose the testing condition in parenthesis.
• a == true is same as just a in if condition
• Test conditions must always yield bool values

  // this code is valid in python and java but not in go
  price := 45
  if price {
      fmt.Println("error")
  }
  

• Syntax

  if a > 45 {
      // statements
  } else if a < 54 {
      // statements
      // you can have multiple else ifs 
  } else {
      // statements
  }
  

Simple If

• val and err are variables scoped to the if statement only

  if val, err := strconv.Atoi("45"); err == nil {
      fmt.Println(err)
  } else {
      fmt.Println(val)
  }
  
  // the above is equivalent to 
  val, err := strconv.Atoi("45")
  if err == nil{
      // ..
  } else {
      // ...
  }
  

• Example of scoping

  if a := 56; a > 40 {
      fmt.Println("hello")
  } else {
      fmt.Println("tello")
  }
  fmt.Println(a) 
  // error : undefined: a
  

Switch Statements

Go converts switch statements to if statements behind the scenes

• The purpose of switch statements is to make very long if statements readable
• Go adds a break statement to each case close automatically. In other programming languages an explicit break is mandatory.

  language := "go"
  switch language {
      case "python":
          // statements
      case "go", "golang":
          // its like using the logical or operator   
      default:
          // equivalent to else clause
  }
  

• The default clause is equivalent to the else clause in if statements
• The default clause is not mandatory.

  n := 5
  // comparing bool to another bool value 
  switch true { // equivalent to just switch
      case n%2 == 0:
          // statements
      case n%2 != 0:
          // statements
  }
  

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Last updated: 2022-05-21