Delphi 在字符串中查找下划線

Question

我有兩個名為“ver1”和“ver2”的字符串，字符串中的輸入如下所示：

Ver1: B2CD1 Ver2: B3A10

有時它看起來像這樣：

Ver1: B2CD1_A1 Ver2: B3A10_DE

我的問題：如何在“_”后面的兩個字符串中進行搜索並從中返回一個值？

順便說一下，該功能用於軟件版本比較。 請在我的問題中給我建議，而不是我的全部職能。

謝謝

uses
  Classes, SysUtils, StrUtils, Forms, Controls, Graphics, Dialogs, StdCtrls;


type

  { TForm1 }

  TForm1 = class(TForm)
    Button1: TButton;
    Edit1: TEdit;
    Edit2: TEdit;
    Memo1: TMemo;
    procedure Button1Click(Sender: TObject);
    procedure Edit1Change(Sender: TObject);
    procedure Memo1Change(Sender: TObject);
  private

  public

  end;

var
  Form1: TForm1;

implementation

{$R *.lfm}

function isSoftwareGreater(ver1,ver2 : string) : byte;
var i : integer;
    tmp1,tmp2 : string;
    cver1,cver2 : int64;

begin
{
  Return values:
      0: versions are equal
      1: ver1 is bigger then ver2
      2: ver2 is bigger then ver1
    253: ver1 is too big (could not be converted to int64)
    254: ver2 is too big (could not be converted to int64)
}

  tmp1 := '';
  tmp2 := '';

  for i := 1 to length(ver1) do
   begin
    if (ver1[i] in ['a'..'z']) or (ver1[i] in ['A'..'Z']) then
     tmp1 := tmp1 + inttostr(Ord(ver1[i]));
    if (ver1[i] in ['0'..'9']) then
     tmp1 := tmp1 + ver1[i];
   end;
  for i := 1 to length(ver2) do
   begin
    if (ver2[i] in ['a'..'z']) or (ver2[i] in ['A'..'Z']) then
     tmp2 := tmp2 + inttostr(Ord(ver2[i]));
    if (ver2[i] in ['0'..'9']) then
     tmp2 := tmp2 + ver2[i];
   end;

  if not TryStrToInt64(tmp2,cver2) then
   begin
    isSoftwareGreater := 254;
    exit;
   end;
  if not TryStrToInt64(tmp1,cver1) then
   begin
    isSoftwareGreater := 253;
    exit;
   end;

  if ver1 > ver2 then
    isSoftwareGreater := 1
  else if ver2 > ver1 then
    isSoftwareGreater := 2
  else if ver1 = ver2 then
    isSoftwareGreater := 0;

end;
 

Answer 1

您可以使用Pos() 函數搜索字符串。 它返回找到的字符的索引，如果沒有找到則返回 0。

var
    Index     : Integer;
    SubString : String;
begin
    Index := Pos('_', Ver1);
    if Index > 0 then
        SubString := Copy(Ver1, Index + 1, MAXINT)
    else
        SubString := '';
end;

如果要提取兩個標記之間的文本，則必須按上圖所示搜索第一個，然后從第一個之后開始搜索第二個。 Pos() 有一個可選的第三個參數來指定從哪里開始搜索。 這給出：

var
    Index1    : Integer;
    Index2    : Integer;
    SubString : String;
begin
    Index1 := Pos('_', Ver1);
    if Index1 > 0 then begin
        Index2 := Pos('_', Ver1, Index1 + 1);
        if Index2 > 0 then
            // We have two underscore, extract text between them
            SubString := Copy(Ver1, Index1 + 1, Index2 - Index1 - 1)
        else
            // Only one underscore, extract text from the first to the end of string
            SubString := Copy(Ver1, Index1 + 1, MAXINT);
    end
    else
        SubString := '';
end;

Answer 2

您可以使用ContainsStr()檢查字符串是否有'_' ，然后使用SubString()和IndexOf()

function GetString(const AString, ASubString: string): string;
begin
  Result:= EmptyStr;
  if ContainsStr(AString, ASubString) then
    Result:= AString.Substring(Astring.IndexOf(ASubString)+1, AString.Length);
end;