Map Declaration and Initialization

We can declare an empty map using the make() function. Below is the syntax we need to follow:

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var mapName = make(map[keyType]valueType)
// or
mapName := make(map[keyType]valueType)

Here, mapName is the name of the map, keyType is the expected type of the keys, and valueType is the expected type of the values. The term map is a keyword.

We can declare a map called courseData with keys of type string and values of type int.

If we attempt to output this map, we will receive an output indicating an empty map:

We can initialize a map with some data using the following syntax:

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var mapName = map[keyType]valueType = {
    key1: value1,    
    key2: value2,
    key3: value 3,
    …
}

Note

You can place or omit spaces in the map declaration syntax; therefore, both map[keyType]valueType and map [keyType] valueType are valid.

Using the above syntax, we can create a map that has some initial data in it: