Array of string from Arraylist of Arraylist

I want to create an array of string from Arraylist of Arraylist.

Here is a code:

ArrayList MainList = new ArrayList();

ArrayList subList = new ArrayList();
subList.Add("A");
subList.Add("Apple");
MainList.Add(subList);

subList = new ArrayList();
subList.Add("B");
subList.Add("Banana");
MainList.Add(subList);

subList = new ArrayList();
subList.Add("C");
subList.Add("Caret");
MainList.Add(subList);

string[] AllList = { "A", "Apple", "B", "Banana", "C", "Caret" };
string[] OnlySome = { "Apple", "Banana", "Caret" };

I know we can do it using for each loop but how can I get AllList 开发者_如何学Pythonand OnlySome string array using LINQ Query ?

Thanks

Sure:

var allList = 
    MainList.
        Cast<ArrayList>().
        SelectMany(a => a.Cast<string>()).
        ToArray();

var onlySome = 
    MainList.
        Cast<ArrayList>().
        Select(a => 
            a.Cast<string>().
                Skip(1).
                First()).
        ToArray();

I wasn't sure what was the exact condition for OnlySome, therefore I thought 2 options,

• Select every other element (odd indexed, even location) onlySome1

• Select any string which has a length greater than 1 onlySome2

      var allList = (from al in MainList.ToArray()
                    from s in (al as ArrayList).ToArray()
                    select s as string).ToArray();
  
      // if you want to select every other element
      var onlySome1 = allList.Where((s, index) => index % 2 == 1).ToArray();
  
      // if you want to select all the strings with 2 or more characters.
      var onlySome2 = allList.Where(s => (s as string).Length > 1).ToArray();