从内存结构到管理机制, String 远比 Char 要复杂.
因此, 面对这种情况(要定位的是 Char) Pos 还有优化的余地; 优化后速度会提升 5 倍左右.
测试效果图:
![](https://www.cnblogs.com/images/cnblogs_com/del/124874/o_83182.gif)
unit Unit1; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls; type TForm1 = class(TForm) Button1: TButton; procedure Button1Click(Sender: TObject); end; var Form1: TForm1; implementation {$R *.dfm} //自定义的 Pos 函数 function MyPos(c: Char; const str: string): Integer; var i: Integer; begin Result := 0; for i := 1 to Length(str) do if c = str[i] then begin Result := i; Exit end; end; {对比测试} procedure TForm1.Button1Click(Sender: TObject); var s: string; c: Char; i: Integer; n: Cardinal; begin s := 'abcdefghijklmnopqrstuvwxyz'; Randomize; c := Chr(Random(26) + 97); {随机一个 a..z 的字符} {用 Pos 函数} n := GetTickCount; for i := 1 to 1000000 do Pos(c,s); n := GetTickCount - n; Text := IntToStr(n) + ' - '; {用自定义的 MyPos 函数} n := GetTickCount; for i := 1 to 1000000 do MyPos(c,s); n := GetTickCount - n; Text := Text + IntToStr(n); Button1.Caption := 'Pos 与 MyPos 速度测试'; end; end.