Split a string into an array of strings based on a delimiter

you can use the TStrings.DelimitedText property for split an string

check this sample

program Project28;

{$APPTYPE CONSOLE}

uses
  Classes,
  SysUtils;

procedure Split(Delimiter: Char; Str: string; ListOfStrings: TStrings) ;
begin
   ListOfStrings.Clear;
   ListOfStrings.Delimiter       := Delimiter;
   ListOfStrings.StrictDelimiter := True; // Requires D2006 or newer.
   ListOfStrings.DelimitedText   := Str;
end;


var
   OutPutList: TStringList;
begin
   OutPutList := TStringList.Create;
   try
     Split(':', 'word:doc,txt,docx', OutPutList) ;
     Writeln(OutPutList.Text);
     Readln;
   finally
     OutPutList.Free;
   end;
end.

UPDATE

See this link for an explanation of StrictDelimiter.

There is no need for engineering a Split function. It already exists, see: Classes.ExtractStrings.

Use it in a following manner:

program Project1;

{$APPTYPE CONSOLE}

uses
  Classes;

var
  List: TStrings;
begin
  List := TStringList.Create;
  try
    ExtractStrings([':'], [], PChar('word:doc,txt,docx'), List);
    WriteLn(List.Text);
    ReadLn;
  finally
    List.Free;
  end;
end.

And to answer the question fully; List represents the desired array with the elements:

List[0] = 'word'
List[1] = 'doc,txt,docx'

You can use StrUtils.SplitString.

function SplitString(const S, Delimiters: string): TStringDynArray;

Its description from the documentation:

Splits a string into different parts delimited by the specified delimiter characters.

SplitString splits a string into different parts delimited by the specified delimiter characters. S is the string to be split. Delimiters is a string containing the characters defined as delimiters.

SplitString returns an array of strings of type System.Types.TStringDynArray that contains the split parts of the original string.