How to find values in a string

Problem/Question/Abstract:

I have a string which contains values separated by "," and not necessarily in numeric order (1, 50, 100, 2, 5, 10, ...). What is the best and fastest way to search through this string to find a value, for example 100?

Answer:

type
  TIntArray = array of integer

procedure StringToIntArray(const S: string; var List: TIntArray);
{ Converts "S" to an array of integer -> "List" }
const
  ValidChars: set of char = ['0'..'9', '-'];
var
  Ix, Ix2, Len, C: Integer;
  SubStr: string;
  Value, Code: Integer;
begin
  Len := Length(S);
  SetLength(List, Len);
  if Len = 0 then
    Exit;
  C := 0;
  Ix := 1;
  while Ix <= Len do
  begin
    while (Ix <= Len) and (not (S[Ix] in ValidChars)) do
      Inc(Ix);
    Ix2 := Ix;
    while (Ix <= Len) and (S[Ix] in ValidChars) do
      Inc(Ix);
    SubStr := Copy(S, Ix2, Ix - Ix2);
    Val(SubStr, Value, Code);
    if Code = 0 then
    begin
      List[C] := Value;
      Inc(C);
    end;
  end;
  SetLength(List, C);
end;

function FindValue(Value: Integer; List: TIntArray): Integer;
{ Returns index of requested value, or -1 if not found. }
var
  Ix: Integer;
begin
  Result := -1;
  Ix := 0;
  while Ix < Length(List) do
  begin
    if List[Ix] = Value then
    begin
      Result := Ix;
      Exit;
    end;
    Inc(Ix);
  end;
end;

Example:

StringToIntArray('(1, 50, 100, 2, 5, 10,.....)', MyIntArray)

sets the contents of MyIntArray to [1,50,100,2,5,10].
then FindValue(100, MyIntArray) returns 2, as MyIntArray[2] = 100;