docs: public final VariableNumMap getVariablesByNamePrefix(String namePrefix) {
      int[] newNums = new int[nums.length];
      String[] newNames = new String[nums.length];
      Variable[] newVars = new Variable[nums.length];
  
      int numFilled = 0;
      for (int i = 0; i < nums.length; i++) {
        if (names[i].startsWith(namePrefix)) {
          newNums[numFilled] = nums[i];
          newNames[numFilled] = names[i];
          newVars[numFilled] = vars[i];
          numFilled++;
        }
      }
      return VariableNumMap.fromSortedArrays(newNums, newNames, newVars, numFilled);
    }