String analysieren und Textteil ersetzen

[SProske]

Rein aus Spaß mal eine Umsetzung mit Regulären Ausdrücken und TDictionary:

Delphi-Quellcode:

uses
  System.SysUtils, RegularExpressions, System.Generics.Collections;

type
  THashtagReplacer = class
  strict private
    FDic: TDictionary<string, string>;
    function InternalReplaceHashtag(const Match: TMatch): string;
  public
    constructor Create;
    destructor Destroy;override;
    procedure AddKeyValue(const Key, Value: string);
    function DoReplace(const Input: string): string;
  end;
    
{ THashtagReplacer }

procedure THashtagReplacer.AddKeyValue(const Key, Value: string);
begin
  FDic.Add(Key, Value);
end;

constructor THashtagReplacer.Create;
begin
  inherited;
  FDic := TDictionary<string,string>.Create;
end;

destructor THashtagReplacer.Destroy;
begin
  FDic.Free;
  inherited;
end;

function THashtagReplacer.DoReplace(const Input: string): string;
begin
  Result := TRegex.Replace(Input, '#[^#]+#', InternalReplaceHashtag);
end;

function THashtagReplacer.InternalReplaceHashtag(const Match: TMatch): string;
begin
  if not FDic.TryGetValue(Match.Value, Result) then
    Result := Match.Value;
end;

Aufruf wäre dann z.B. so

Delphi-Quellcode:

var
  TestString: string;
  Replacer: THashtagReplacer;
begin           
  TestString := '#test1# Hallo Welt #test2##test3#';
  Replacer := THashtagReplacer.Create;
  try
    Replacer.AddKeyValue('#test1#', 'foo');
    Replacer.AddKeyValue('#test2#', 'bar');
    TestString := Replacer.DoReplace(TestString);
    WriteLn(TestString); //-> foo Hallo Welt bar#test3#
    ReadLn;
  finally
    Replacer.Free;
  end;
end.