How to check if value exists in struct and save another value in array

Question

I'm not exactly sure how to do this in Go, I'm just starting to work with it so I'm not familiar on how it should be done.

The idea is this: I have a struct created inside a function:

XSiteGroup := struct {
        siteURL string
        siteIDs []string
    }{}

I have implemented a request that gets an array of objects; this objects have the following structure:

{
   "siteId": "",
   "merchantName": "",
   "friendlyTitle": "",
   "url": ""
 }

What I'm trying to do is loop through that array and store each url I find as a "key" without duplicates, and then store the siteId value of each object on the siteIDs array of the struct XSiteGroup. So let's say the following scenario:

{
   "siteId": "5050",
   "merchantName": "",
   "friendlyTitle": "",
   "url": "url1.com"
},
{
   "siteId": "4050",
   "merchantName": "",
   "friendlyTitle": "",
   "url": "url2.com"
},
{
   "siteId": "8060",
   "merchantName": "",
   "friendlyTitle": "",
   "url": "url1.com"
}

Having the result from above, I would need to store something like:

{
  siteURL: "url1.com",
  siteIDs: ["5050", "8060"]
}

I have something like this at the moment to loop the array of sites I have:

for _, site := range xwebsites {
        u, _ := url.Parse(site.URL)
        urlString := strings.ReplaceAll(u.Host, "www.", "")

        // So I'm thinking here I should handle the struct I created to store values 
        }

Please let me know if I'm not clear or what additional information is needed.

Answer 1

If the value doesn't exist, you have to create it. You can check that with value, ok := map[key].

type xsitegroup struct {
  url     string
  ids     []string
}

// A mapping between urls and their site groups.
sitegroups := make(map[string]*xsitegroup)
    
for _, website := range xwebsites {
        url := website["url"]

        sitegroup, ok := sitegroups[url]

        // A sitegroup for this URL does not exist
        if !ok {
            // Create the sitegroup
            sitegroup = &xsitegroup{ url: url, ids: []string{} }
            // Add it to the mapping
            sitegroups[url] = sitegroup
        }
     
        // Append the site id.   
        sitegroup.ids = append(sitegroup.ids, website["siteId"])
}

Demonstration