Conditional declaring arrays in two-dimensional char array?

Question

I have a two-dimensional char array declared with four strings.

private static string string1 = "abcde";
private static string string2 = "ABCDE";
private static string string3 = "12345";
private static string string4 = "67890";

public string selectChars(bool includeOne, bool includeTwo, bool includeThree, bool includeFour)
{
   char[][] charGroups = new char[][] 
   {
       string1.ToCharArray(),
       string2.ToCharArray(),
       string3.ToCharArray(),
       string4.ToCharArray()
   };
}

I want to declare and initialize the array such that the string add is conditional based on four bool flags. For example, if includeOne and includeThree are true, I want to end up with a charGroup[2][5] having used string1 and string 3.

(This is existing code where I don't want to radically change the rest of the code. if I can conditionally declare the array in that block, I'm done.)

Answer 1

The manner you want is like a list, so it's better implement it by list and then return an array by ToArray:

public string selectChars(bool includeOne, bool includeTwo, bool includeThree, bool includeFour)
{
        List<char[]> chars = new List<char[]>();
        string string1 = "";
        if (includeOne)
            chars.Add(string1.ToCharArray());
        if(includeTwo) ....

        char[][] charGroups = chars.ToArray();
}

Answer 2

I don't have the VM going but I think this should work...

private static string string1 = "abcde";
private static string string2 = "ABCDE";
private static string string3 = "12345";
private static string string4 = "67890";

public string selectChars(bool includeOne, bool includeTwo, bool includeThree, bool includeFour)
{
   char[][] charGroups = new char[][] 
   {
       include1 ? string1.ToCharArray() : new char[0],
       include3 ? string2.ToCharArray() : new char[0],
       include3 ? string3.ToCharArray() : new char[0],
       include4 ? string4.ToCharArray() : new char[0]
   };
}

If all you want to do is include the string as a character array if their respective flag is set then I think this will do the trick. It is using the conditional operator to include the left side of ':' (if includeX is true) otherwise include the right side.

Answer 3

1) Count up how many strings need to be added (how many of the flags are true).

2) char[][] charGroups = new char[count][]; (might need to be char[][count]; I'm operating on very little sleep)

3) Init an index to 0; for each flag, if it's set, put the appropriate char[] into that index, and increment the index.

But why, oh why are you taking the String s apart into char[] s? The String class is your friend. It wants to make your life easier.