从字符串中删除数字

Question

我想知道如何从String中删除数字.我尝试使用StringReplace,我不知道如何告诉函数我想要替换数字.

这是我试过的:

StringReplace(mString, [0..9], '', [rfReplaceAll, rfIgnoreCase]);

Answer 1

简单但有效.可以优化,但应该为您提供您需要的开始:

function RemoveNumbers(const aString: string): string;
var
  C: Char;
begin
  Result := '';
  for C in aString do begin
      if not CharInSet(C, ['0'..'9']) then
      begin
        Result := Result + C;
      end;
    end;
end;

Answer 2

相当快速的inplace版本.

procedure RemoveDigits(var s: string);
var
  i, j: Integer;
  pc: PChar;
begin
  j := 0;
  pc := PChar(@s[1]);
  for i := 0 to Length(s) - 1 do
    if pc[i] in ['0'..'9'] then 
               //if CharInSet(pc[i], ['0'..'9']) for Unicode version
      Inc(j)
    else
      pc[i - j] := pc[i];
  SetLength(s, Length(s) - j);
end;

Answer 3

这与Nick的版本具有相同的输出,但这是短字符串的3倍以上.文本越长,差异越大.

function RemoveNumbers2(const aString: string): string;
var
  C:Char; Index:Integer;
begin
  Result := '';
  SetLength(Result, Length(aString));
  Index := 1;
  for C in aString do
    if not CharInSet(C, ['0' .. '9']) then
    begin
      Result[Index] := C;
      Inc(Index);
    end;
  SetLength(Result, Index-1);
end;

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