前边的都不太好
procedure TForm1.BitBtn1Click(Sender: TObject);
var
s: string;
i: integer;
begin
s:= 'AB2az3C';
i := 1;
while i <= Length(s) do
begin
if not (((Ord(s[i]) >= 65) And (Ord(s[i])<=90)) or ((Ord(s[i]) >= 97) And (Ord(s[i])<=122))) then
begin
dec(i);
break;
end;
inc(i);
end;
showmessage(copy(s,1,i));
end;
function TForm1.GetAlpha(Astr: string): string;
var
i:integer;
begin
Result:='';
for i:=1 to Length(Astr) do
if Astr[i] in ['a'..'z','A'..'Z'] then Result:=Result+Astr[i];
end;
procedure TForm1.Button1Click(Sender: TObject);
var
s,ss: string;
i: integer;
begin
ss:= '';
s:= 'AB2az3C';
for i:=0 to Length(s) do
begin
if ((Ord(s[i]) >= 65) And (Ord(s[i])<=90)) or ((Ord(s[i]) >= 97) And (Ord(s[i])<=122)) then
ss:= ss+s[i];
end;
showmessage(ss);
end;