How can I write an array of maps [golang]

arrays, data-structures, go

Solution

Working example (click to play):

something := []string{"coins", "notes", "gold?"}

thisMap := make(map[string][]map[string]int)

for _, v := range something {
    aMap := map[string]int{
        "random": 12,
    }

    thisMap[v] = append(thisMap[v], aMap)
}

When iterating over the newly created `thisMap`, you need to make room for the new value `aMap`. The builtin function `append` does that for you when using slices. It makes room and appends the value to the slice.

If you're using more complex data types that can't be initialized as easily as slices, you first have to check if the key is already in the map and, if it is not, initialize your data type. Checking for map elements is documented here. Example with maps (click to play):

thisMap := make(map[string]map[string]int)

for _, v := range something {
    if _, ok := thisMap[v]; !ok {
        thisMap[v] = make(map[string]int)
    }
    thisMap[v]["random"] = 12
}

Problem

I have a map which has as value an array of maps. Example: ``` thisMap["coins"][0] = aMap["random":"something"] thisMap["notes"][1] = aMap["not-random":"something else"] thisMap["coins"][2] = aMap["not-random":"something else"] ``` I can't figure it out how to do this as `go` seems to allow setting data only at one level when you deal with `maps [name][value] = value`. So far I have this code which fails ``` package main func main() { something := []string{"coins", "notes", "gold?", "coins", "notes"} thisMap := make(map[string][]map[string]int) for k, v := range something { aMap := map[string]string{ "random": "something", } thisMap[v] = [k]aMap } } ``` Edit: The slice values ("coins", "notes" etc ) can repeat so this is the reason why I need use an index `[]` .

Original source