Delphi中常用字符串处理函数

秦浩凌妈妈 發表於 2019-6-21 13:30:00

1.copy(str,pos,num) 从str字符串的pos处开始,截取num个字符的串返回. 假设str为'abcdef',copy(str,3,2)='cd',copy(str,4,10)='def' 2.concat(str1,str2{,strn}) 把各自变量连接起来,返回连接后的字符串(长度不能超过255) 3.length(str) 返回str的字符个数,即其长度. 4.pos(obj,target) 在target字符串中找出第一个出现obj的第一个字符位置,如果找不到,返回0. 5.AnsiStrLastChar('你好')结果是“好”。如果有半个汉字出现,返回这半个汉字。二者字符串长度分别为2和1。 6.CompareStr- 区分大小写 7.CompareText - 不区分大小写 8.StringReplace(const S, OldPattern, NewPattern: string;Flags: TReplaceFlags): string; 字符串替换函数，需要引用SysUtils单元 rfReplaceAll：全部替换 rfIgnoreCase：忽略大小写 使用方法Lg： 　　str：＝＇01231142211 ：655767＇；//需要把：替换成---- s:=StringReplace(str,'：','----',); For Example：
var aStr: String; begin aStr := 'This is a book, not a pen!'; ShowMessage(StringReplace (aStr, 'a', 'two', [])); //This is two book, not a pen!只替换了第一个符合的字 ShowMessage(StringReplace (aStr, 'a', 'two', )); //This is two book, not two pen!替换了所有符合的字 aStr := 'This is a book, not A pen!'; ShowMessage(StringReplace (aStr, 'a', 'two', )); //This is two book, not A pen!只替换了符合的字(小写a) ShowMessage(StringReplace (aStr, 'a', 'two', )); //This is two book, not two pen!不管大小写替换了所有符合的字 end;
9.delete 是删除一个字符串中的某部分字符 用法是 delete(str,//被删除的字符串 index,//从第几个字符开始删除 count //删除几个 ); Delete(S, 2, 2); 就是从S中的第二个开始删除，删除2个字符即2、3.所以结果是145. //////////////////////////////////////////////////////// LEFTSTR, MIDSTR, RIGHTSTR的介绍 这几个函数都包含在StrUtils中，所以需要uses StrUtils; 假设字符串是 Dstr := ’Delphi is the BEST’, 那么 LeftStr(Dstr, 5) := ’Delph’ MidStr(Dstr, 6, 7) := ’i is th’ RightStr(Dstr, 6) := ’e BEST’
 
8.{判断字符是否是数字} function IsDigit(ch: char): boolean; begin Result := ch in ['0'..'9']; end; 
9、{判断字符是否是大写字符} function IsUpper(ch: char): boolean; begin Result := ch in ['A'..'Z']; end; 10、{判断字符是否是小写字符} function IsLower(ch: char): boolean; begin Result := ch in ['a'..'z']; end; 11、{转换为大写字符} function ToUpper(ch: char): char; begin Result := chr(ord(ch) and $DF); end; 12、{转换为小写字符} function ToLower(ch: char): char; begin Result := chr(ord(ch) or $20); end; { Capitalizes first letter of every word in s } 
function Proper(const s: string): string; var i: Integer; CapitalizeNextLetter: Boolean; begin Result := LowerCase(s); CapitalizeNextLetter := True; for i := 1 to Length(Result) do begin if CapitalizeNextLetter and IsLower(Result) then Result := ToUpper(Result); CapitalizeNextLetter := Result = ' '; end; end; //////////////////////////////////////////////////////////// 13.{返回两个子字符串之间字符的个数} Function p2pcount( s, ss1, ss2 : string ): integer; var i, j, slen : integer; begin i := pos( ss1, s ); j := pos( ss2, s ); slen := Length(ss2); if j >= i then Result := j - i + slen else Result := 0; end; 14.{更快速的字符查询,快40%} function ScanStr(ToScan: PChar; Sign: Char):PChar; begin Result:= nil; if ToScan <> nil then while (ToScan^ <> #0) do begin if ToScan^ = Sign then begin Result:= ToScan; break; end; inc(ToScan); end; end; ///////////////////////////// 15.替换字符串中子串的函数,他可以从字符串中找出指定子串,并替换为另一子串。 function replacing(S,source,target:string):string; var site,StrLen:integer; begin {source在S中出现的位置} site:=pos(source,s); {source的长度} StrLen:=length(source); {删除source字符串} delete(s,site,StrLen); {插入target字符串到S中} insert(target,s,site); {返回新串} replacing:=s; end; /////////////////////// 另两个替换字符串中子串的函数 function repl_substr( sub1, sub2, s: string ): string; var i: integer; begin repeat i := pos( sub1, s ) ; if i > 0 then begin delete( s, i, Length(sub1)); insert( sub2, s, i ); end; until i < 1; Result := s; end; function ReplaceText(const S,ReplacePiece,ReplaceWith: String):String; Var Position: Integer; TempStr: String; begin Position := Pos(ReplacePiece,S); if Position > 0 then Begin TempStr := S; Delete(TempStr,1,Position-1+Length(ReplacePiece)); Result := Copy(S,1,Position-1)+ReplaceWith+ReplaceText(TempStr,ReplacePiece,ReplaceWith) End else Result := S; end; //////////////////////// 替换全部子字符串的函数 function ReplaceSub(str, sub1, sub2: String): String; var aPos: Integer; rslt: String; begin aPos := Pos(sub1, str); rslt := ''; while (aPos <> 0) do begin rslt := rslt + Copy(str, 1, aPos - 1) + sub2; Delete(str, 1, aPos + Length(sub1)); aPos := Pos(sub1, str); end; Result := rslt + str; end; ///////////////////////// 在字符串左右填充指定数量的指定字符 function UT_PadString(inString :string; maxLength :integer; padChar :char; left :boolean) :string; begin result := inString; while (Length(result) < maxLength) do if (left) then result := padChar + result else result := result + padChar; end; ///////////////////////////////////// 提取字符串中指定子字符串前的字符串 Function Before ( string ; Var S:string ) : string ; Var F : Word ; begin F := POS (Src,S) ; if F=0 then Before := S else Before := COPY(S,1,F-1) ; end ; ////////////////////////////////// 提取字符串中指定子字符串后的字符串 Function After ( string ; Var S:string ) : string ; Var F : Word ; begin F := POS (Src,S) ; if F=0 then After := '' else After := COPY(S,F+length(src),length(s)) ; end ; //////////////////////////////////// 判断字符串是否可以转换为整数 function IsIntStr(const S: string): boolean; begin Result:=StrToIntDef(S,0)=StrToIntDef(S,1); end; ////////////////////////////////////// 从字符串中删除指定字符串 procedure RemoveInvalid(what, where: string): string; var tstr: string; begin tstr:=where; while pos(what, tstr)>0 do tstr:=copy(tstr,1,pos(what,tstr)-1) + copy(tstr,pos(what,tstr)+length(tstr),length(tstr)); Result:=tstr; end; 用法: NewStr:=RemoveInvalid('<invalid>','This <invalid> is my string and I wan to remove the word <invalid>'); /////////////////////////////////////////// 根据某个字符分割字符串的函数 procedure SeparateTerms(s : string;Separator : char;Terms : TStringList); { This browses a string and divide it into terms whenever the given separator is found. The separators will be removed } var hs : string; p : integer; begin Terms.Clear; // First remove all remaining terms if Length(s)=0 then // Nothin' to separate Exit; p:=Pos(Separator,s); while P<>0 do begin hs:=Copy(s,1,p-1); // Copy term Terms.Add(hs); // Add to list Delete(s,1,p); // Remove term and separator p:=Pos(Separator,s); // Search next separator end; if Length(s)>0 then Terms.Add(s); // Add remaining term end; ========== = 用法 ========== var Terms : TStringList; i : integer; const TestStr = '1st term;2nd term;3rd term'; begin Terms:=TStringList.Create; SeparateTerms(TestStr,';',Terms); for i:=0 to terms.Count-1 do ShowMessage(Terms.Strings); Terms.Free; end; ///////////////////////////// 根据一组字符分割字符串的函数 type Charset = set of Char; var f : Text; s : String; procedure WriteStringSplitted(var s: String; Separators: Charset); var a,e : Integer;{anfang und ende des w鰎tchens} begin a := 1; for e := 1 to Length(s) do if s in Separators then begin WriteLn(Copy(s, a, e-a)); a := e + 1; end; WriteLn(Copy(s, a, e-a+1)); end; begin Assign(f, 'c:/dingsbums/text.txt'); Reset(f); while not EOF(f) do begin ReadLn(f,s); WriteStringSplitted(s, [':', ',']); end; Close(f); end. ////////////////////////////////////////////////// {===============================================================} { 函数: RESULTSTRING = HexToBin(HEXSTRING) { 目的 : 把十六进制字符串转换为二进制字符串 { {===============================================================} { 函数: RESULTINTEGER = HexCharToInt(HEXCHAR) { 目的 : 转换一个十六进制字符为整数 {===============================================================} { 函数: RESULTSTRING = HexCharToBin(HEXCHAR) { 目的 : 转换一个十六进制字符为二进制字符串 {===============================================================} { 函数: RESULTINTEGER = Pow(BASE,POWER) { 目的 : 指数函数 {===============================================================} { 函数: RESULTINTEGER = BinStrToInt(BINSTRING) { 目的 : 把二进制字符串转换为整数 {===============================================================} { 函数: RESULTSTRING = DecodeSMS7Bit (PDUSTRING) { 目的 : 解码一个7-bit SMS (GSM 03.38) 为ASCII码 {===============================================================} { 函数:RESULTSTRING = ReverseStr (SOURCESTRING) { 目的 : 反转一个字符串 {===============================================================} unit BinHexTools; interface function HexToBin(HexNr : string): string; function HexCharToInt(HexToken : char):Integer; function HexCharToBin(HexToken : char): string; function pow(base, power: integer): integer; function BinStrToInt(BinStr : string) : integer; function DecodeSMS7Bit(PDU : string):string; function ReverseStr(SourceStr : string) : string; implementation uses sysutils, dialogs; function HexCharToInt(HexToken : char):Integer; begin {if HexToken>#97 then HexToken:=Chr(Ord(HexToken)-32); { use lowercase aswell } Result:=0; if (HexToken>#47) and (HexToken<#58) then { chars 0....9 } Result:=Ord(HexToken)-48 else if (HexToken>#64) and (HexToken<#71) then{ chars A....F } Result:=Ord(HexToken)-65 + 10; end; function HexCharToBin(HexToken : char): string; var DivLeft : integer; begin DivLeft:=HexCharToInt(HexToken); { first HEX->BIN } Result:=''; { Use reverse dividing } repeat { Trick; divide by 2 } if odd(DivLeft) then { result = odd ? then bit = 1 } Result:='1'+Result { result = even ? then bit = 0 } else Result:='0'+Result; DivLeft:=DivLeft div 2; { keep dividing till 0 left and length = 4 } until (DivLeft=0) and (length(Result)=4); { 1 token = nibble = 4 bits } end; function HexToBin(HexNr : string): string; { only stringsize is limit of binnr } var Counter : integer; begin Result:=''; for Counter:=1 to length(HexNr) do Result:=Result+HexCharToBin(HexNr); end; function pow(base, power: integer): integer; var counter : integer; begin Result:=1; for counter:=1 to power do Result:=Result*base; end; function BinStrToInt(BinStr : string) : integer; var counter : integer; begin if length(BinStr)>16 then raise ERangeError.Create(#13+BinStr+#13+ 'is not within the valid range of a 16 bit binary.'+#13); Result:=0; for counter:=1 to length(BinStr) do if BinStr='1' then Result:=Result+pow(2,length(BinStr)-counter); end; function DecodeSMS7Bit(PDU : string):string; var OctetStr : string; OctetBin : string; Charbin: string; PrevOctet: string; Counter: integer; Counter2 : integer; begin PrevOctet:=''; Result:=''; for Counter:=1 to length(PDU) do begin if length(PrevOctet)>=7 then { if 7 Bit overflow on previous } begin if BinStrToInt(PrevOctet)<>0 then Result:=Result+Chr(BinStrToInt(PrevOctet)) else Result:=Result+' '; PrevOctet:=''; end; if Odd(Counter) then { only take two nibbles at a time } begin OctetStr:=Copy(PDU,Counter,2); OctetBin:=HexToBin(OctetStr); Charbin:=''; for Counter2:=1 to length(PrevOctet) do Charbin:=Charbin+PrevOctet; for Counter2:=1 to 7-length(PrevOctet) do Charbin:=OctetBin+Charbin; if BinStrToInt(Charbin)<>0 then Result:=Result+Chr(BinStrToInt(CharBin)) else Result:=Result+' '; PrevOctet:=Copy(OctetBin,1,length(PrevOctet)+1); end; end; end; function ReverseStr(SourceStr : string) : string; var Counter : integer; begin Result:=''; for Counter:=1 to length(SourceStr) do Result:=SourceStr+Result; end; end.
 
转自https://www.cnblogs.com/hhmm99/p/10613708.html 
来源：https://www.cnblogs.com/zyb2016/p/11064047.html

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Delphi中常用字符串处理函数