delphi 判断一个字符串是否只由数字组成
function IsNum(str: string): Boolean;
var
i: Integer;
begin
Result := True;
for i := 1 to Length(str) do
if not (str[i] in ['0'..'9']) then
begin
Result := False;
Break;
end;
end;
var
i: Integer;
begin
Result := True;
for i := 1 to Length(str) do
if not (str[i] in ['0'..'9']) then
begin
Result := False;
Break;
end;
end;