Using 'AsParallel()' / 'Parallel.ForEach()' guidelines?

Question

Looking for a little advice on leveraging AsParallel() or Parallel.ForEach() to speed this up.

See the method I\'ve got (simplified/bastardized

Answer 1

I would prefer to use another data structure like a Set for each alias and then use Set union to merge them.

Something like this

public string[] ExpandAliases(string[] countries){
    // Alias definitions
    var apac = new HashSet { "US", "FR", ...};
    ... 

    var aliases = new HashMap> { {"APAC": apac}, ... };

    var expanded = new HashSet
    foreach(var country in countries){
        if(aliases.Contains(country)
            expanded.Union(aliases[country]);
        else{
            expanded.Add(country);
    }

    return expanded.ToArray();
}

Note: code should be viewed as pseudo-code.