Using Simple example we will learn mapping in Go lang :

1. Go program to illustrate how to create maps

   package main
   import "fmt"
   
   func main() {
   var map_1 map[int]int   // Creating and initializing empty map
   
   if map_1 == nil      // Checking if the map is nil or not
   
           fmt.Println("True")
       } else {
           fmt.Println("False")
       }
   
     	// Creating and initializing a map
       map_2: = map[int]string {
           90: "Math",
           91: "Statistic",
           92: "Python",
           93: "SQL",
           94: "Machine Learning ",
       }
       fmt.Println("Map-2: ", map_2)
   }
   

   Output :

   PS C:\GO_Language\Maps> go run maps.go
   True
   Map-2:  map[90:Math 91:Statistic 92:Python 93:SQL 94:Tablue]
   

2. Go program to illustrate, iterate a map using the range for loop. The value of this loop may vary because the map is an unordered collection

   package main
   import "fmt"
   func main() {
       M_a_p: = map[int]string {
           90: "Math",
           91: "Statistic",
           92: "Python",
           93: "SQL",
           94: " Machine Learning ",
       }
       for id, pet := range m_a_p {
           fmt.Println(id, pet)
       }
   }
   

   Output :

   PS C:\GO_Language\Maps> go run maps1.go
   92 Python
   93 SQL
   94  Machine Learning 
   90 Math
   91 Statistic
   

       

      Using the Mark Function:

   1. Go program to illustrate the difference between declaring an empty map using with the make()function and without it

      package main
      
      import "fmt"
      
      func main() {
          var My_course = make(map[float64]string)
          fmt.Println(My_map)
      
          My_course[1.3] = "Data Scientist"
          My_course[1.5] = "Data Analyst"
          fmt.Println(My_course)
      }
      

      Output :

      PS C:\GO_Language\Maps> go run maps2.go
      map[]
      map[1.3:Data Scientist 1.5:Data Analyst]
      

   2. Go program to illustrate the difference between declaring an empty map using with the make()function and without it.

      package main
      
      import "fmt"
      
      // Main function
      func main() {
      
          // Creating and initializing a map
          m_a_p := map[int]string{
      
              90: "Math",
              91: "Statistic",
              92: "Python",
              93: "SQL",
              94: "Tablue",
          }
      
          // Iterating map using for rang loop
          for id, pet := range m_a_p {
      
              fmt.Println(id, pet)
          }
      }
      

      Output :

      PS C:\GO_Language\Maps> go run maps3.go
      90 Math
      91 Statistic
      92 Python
      93 SQL
      94 Tablue
      

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