How to Properly Initialize Map Fields in Go Structs?

Initialization of Struct Fields with Maps in Go

When initializing a struct containing a map field, it is important to ensure that the map is initialized to avoid nil pointer errors. One approach is to create a constructor function that explicitly initializes the map, such as:

type Graph struct {
  connections map[Vertex][]Vertex
} 

func NewGraph() *Graph {
    var g Graph
    g.connections = make(map[Vertex][]Vertex)
    return &g
}

Another option is to use an "add connection" method that initializes the map if it is empty:

func (g *Graph) add_connection(v1, v2 Vertex) {
  if g.connections == nil {
    g.connections = make(map[Vertex][]Vertex)
  }
  g.connections[v1] = append(g.connections[v1], v2)
  g.connections[v2] = append(g.connections[v2], v1)
}

Some prefer to use constructors due to their clarity and ease of use, while others favor the "add connection" method for its flexibility and potential performance benefits. Ultimately, the best approach depends on the specific requirements of the application.

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