how to get the first string in an array code example

Example 1: csharp first element of array

double[] values;
private List<double[]> valueList = new List<double[]>();
void AddNewValues(double d1, double d2, double d3)
{
   values[0] = d1;
   values[1] = d1;
   values[2] = d1;
   valueList.Add(values);
}

void GetAllFirstValues()
{
   var test = valueList.Where(s => s == typeof(double[0]));
}

Example 2: Check first character of string in array and compare to another array

a = ['ghis', 'rs', 'ea','eat' ,'nentence']

let word = ''
function check(arr){
  let color = ['green']
  for(let i = 0; i < arr.length;i++){
    word += arr[i][0]
  }
 
  for(let j = 0;j < color.length;j++){
    if(word == color[j]){
     return true
    }
  }
  return false
}
console.log(check(a))