ertank 27 Posted July 30, 2019 Hello, I am using Delphi 10.3.2. I used to parse date string "Tue 17 Sep 2019" in an e-mail message using VarToDateTime() which served its purpose well. Now, format changed to "Sunday, 22 September 2019" and that function is not so helpful as before. I am trying not to manually parse the string as it is due to change in the future, too. My questions are; 1- It is always possible one cannot see a simple solution. I appreciate if you can point me to right existing Delphi solution. I could not make StrToDate() working for me even with TFormatSettings provided and even with several different input strings like "22 September 2019", "22/September/2019", etc. 2- It would be great if anybody have a unit or a function he/she can share which handles provided date format like 'dddd, dd mmmm yyyy' and convert the input string to TDateTime using that given format. I do not know C#. I saw several examples of DateTime.ParseExact() which seems like what I am searching for. I might be completely wrong about that though. Thanks & regards, Ertan Share this post Link to post
Guest Posted July 30, 2019 Yes, .net can do the job using System; public class Program { const string dateToParse = "Sunday, 22 September 2019"; const string dateFormat = "dddd, dd MMMM yyyy"; const string dateOutFormat = "yyyy-MM-dd"; public static void Main() { var date = DateTime.ParseExact(dateToParse, dateFormat, System.Globalization.CultureInfo.InvariantCulture); Console.WriteLine(date.ToString(dateOutFormat, System.Globalization.CultureInfo.InvariantCulture)); } } see in action on .net fiddle The C# source code is open source and published on github so you may port it to Delphi. Share this post Link to post
zinpub 0 Posted July 30, 2019 function TForm7.StrToDateFrmt(const iFormat, iDateStr: string): TDateTime; var AYear, AMonth, ADay, AHour, AMinute, ASecond, AMilliSecond: Word; aPos: Integer; procedure InitVars; begin AYear := 1; AMonth := 1; ADay := 1; AHour := 0; AMinute := 0; ASecond := 0; AMilliSecond := 0; end; function GetPart(const iPart: Char): Word; var aYCnt: Integer; begin Result := 0; aYCnt := 0; while (aPos <= High(iFormat)) and (iFormat.Chars[aPos + aYCnt] = iPart) do inc(aYCnt); Result := StrToInt(iDateStr.Substring(aPos, aYCnt)); aPos := aPos + aYCnt; end; begin InitVars; aPos := 0; while aPos <= High(iFormat) do begin case iFormat.Chars[aPos] of 'Y': AYear := GetPart('Y'); 'M': AMonth := GetPart('M'); 'D': ADay := GetPart('D'); 'H': AHour := GetPart('H'); 'N': AMinute := GetPart('N'); 'S': ASecond := GetPart('S'); 'Z': AMilliSecond := GetPart('Z'); else inc(aPos); end; end; Result := EncodeDateTime(AYear, AMonth, ADay, AHour, AMinute, ASecond, AMilliSecond); end; Share this post Link to post
Guest Posted July 30, 2019 @zinpub Nope const dateToParse = 'Sunday, 22 September 2019'; const dateFormat = 'DDDD, DD MMMM YYYY'; const dateOutFormat = 'yyyy-MM-dd'; var date : TDateTime; begin try date := StrToDateFrmt(dateFormat,dateToParse); Writeln( FormatDateTime(dateOutFormat,date) ); except on E: Exception do Writeln(E.ClassName, ': ', E.Message); end; Readln; end. results in EConvertError: 'Sund' ist kein gültiger Integerwert Share this post Link to post
Stefan Glienke 2002 Posted July 30, 2019 6 minutes ago, zinpub said: requires minimal refinement Yeah, minimal... like dealing with every possible language for weekdays the mail could contain regardless the local language of the system the software is running on... 4 3 Share this post Link to post
zinpub 0 Posted July 30, 2019 Well, the transformation of the "any - possible" date is not a task for one function 🙂 Share this post Link to post
ertank 27 Posted July 30, 2019 (edited) Shared C# code conversion is out of my league. I would vote for such a function to be implemented in Delphi by Embarcadero though. For now, I have written something as following. My two versions are parsed OK with that. I might improve this code to have time part and to handle my possible fail cases in the future. I am not after very fast code at the moment. For now I will keep that one. unit uUtils.ParseExact; interface uses System.SysUtils; type TDateTimeHelper = record helper for TDateTime public class function ParseExact(const Value, Format: string; AFormatSettings: TFormatSettings): TDateTime; static; end; implementation procedure GetNumber(const InValue: string; out OutValue: Integer); var Finish: Integer; begin Finish := 1; while CharInSet(InValue.Chars[Finish], ['1', '2', '3', '4', '5', '6', '7', '8', '9', '0']) do Inc(Finish); if not TryStrToInt(InValue.Substring(0, Finish), OutValue) then raise Exception.Create('Cannot convert to number'); end; class function TDateTimeHelper.ParseExact(const Value, Format: string; AFormatSettings: TFormatSettings): TDateTime; label Again; var Day: Integer; Month: Integer; Year: Integer; TempString: string; TempFormat: string; I: Integer; begin Result := 0; TempString := Value.ToLower(); TempFormat := Format.ToLower(); if TempFormat.Contains('mmm') or TempFormat.Contains('mmmm') then begin // month string literals converted to numbers for I := Low(AFormatSettings.LongMonthNames) to High(AFormatSettings.LongMonthNames) do begin TempString := TempString.Replace(AFormatSettings.LongMonthNames[I].ToLower(), I.ToString()); TempString := TempString.Replace(AFormatSettings.ShortMonthNames[I].ToLower(), I.ToString()); end; TempFormat := TempFormat.Replace('mmmm', 'mm'); TempFormat := TempFormat.Replace('mmm', 'mm'); end; if TempFormat.Contains('ddd') or TempFormat.Contains('dddd') then begin // day string literals are simply removed for I := Low(AFormatSettings.LongDayNames) to High(AFormatSettings.LongDayNames) do begin TempString := TempString.Replace(AFormatSettings.LongDayNames[I].ToLower(), EmptyStr); TempString := TempString.Replace(AFormatSettings.ShortDayNames[I].ToLower(), EmptyStr); end; TempFormat := TempFormat.Replace('dddd', EmptyStr); TempFormat := TempFormat.Replace('ddd', EmptyStr); end; TempFormat := TempFormat.Trim(); TempString := TempString.Trim(); Again: // remove non relevant chars at beginning while not CharInSet(TempFormat.Chars[0], ['a'..'z']) do begin TempFormat := TempFormat.Substring(1, MaxInt); TempString := TempString.Substring(1, MaxInt); end; if TempString.Length > 0 then begin case TempFormat[1] of 'd': begin if Day = 0 then GetNumber(TempString, Day); I := 0; while CharInSet(TempString.Chars[I], ['1', '2', '3', '4', '5', '6', '7', '8', '9', '0', AFormatSettings.DateSeparator]) do Inc(I); TempString := TempString.Substring(I, MaxInt); TempFormat := TempFormat.Replace('dd', EmptyStr); goto Again; end; 'm': begin if Month = 0 then GetNumber(TempString, Month); I := 0; while CharInSet(TempString.Chars[I], ['1', '2', '3', '4', '5', '6', '7', '8', '9', '0']) do Inc(I); TempString := TempString.Substring(I, MaxInt); TempFormat := TempFormat.Replace('mm', EmptyStr); goto Again; end; 'y': begin if Year = 0 then GetNumber(TempString, Year); I := 0; while CharInSet(TempString.Chars[I], ['1', '2', '3', '4', '5', '6', '7', '8', '9', '0']) do Inc(I); TempString := TempString.Substring(I, MaxInt); goto Again; end; end; end; if (Day > 0) and (Month > 0) and (Year > 0) then begin try Result := EncodeDate(Year, Month, Day); except raise Exception.Create('uUtils.ParseExact(): Cannot encode.' + sLineBreak + sLineBreak + 'Year: ' + Year.ToString() + sLineBreak + 'Month: ' + Month.MaxValue.ToString() + sLineBreak + 'Day: ' + Day.ToString()); end; end else begin raise Exception.Create('uUtils.ParseExact(): Cannot parse all day, month and year'); end; end; end. Usage is as following: uses uUtils.ParseExact; var ADate: TDateTime; AFormatSettings: TFormatSettings; begin AFormatSettings := TFormatSettings.Create('en-US'); ADate := TDateTime.ParseExact('Sunday, 22 September 2019', 'dddd, dd mmmm yyyy', AFormatSettings); ShowMessage(DateToStr(ADate)); ADate := TDateTime.ParseExact('Sun 15 Sep 2019', 'ddd dd mmm yyyy', AFormatSettings); ShowMessage(DateToStr(ADate)); end; Edited July 30, 2019 by ertank Share this post Link to post
Guest Posted July 31, 2019 Just a sketch It should be possible to translate the format string into a Regular Expression to check the format and extract the values. The current format string dddd, dd mmmm yyyy could be translated to the following regular expression (using the en-US format settings) (Sunday|Monday|Tuesday|Wednesday|Thursday|Friday|Saturday), (\d{2}) (January|February|March|April|May|June|July|August|September|October|November|December) (\d{4}) here a small PoC const dateToParseString = 'Sunday, 22 September 2019'; procedure Test(); var fmtset: TFormatSettings; pattern: string; match: TMatch; day: word; month: word; year: word; begin fmtset := TFormatSettings.Create('en-US'); pattern := // '(' + string.Join('|', fmtset.LongDayNames) + ')' + // "dddd" ', ' + // ", " '(\d{2})' + // "dd" ' ' + // " " '(' + string.Join('|', fmtset.LongMonthNames) + ')' + // "mmmm" ' ' + // " " '(\d{4})'; // "yyyy" match := TRegEx.match(dateToParseString, pattern); if not match.Success then raise Exception.Create('Invalid data'); day := word.Parse(match.Groups.Item[2].Value); month := 1; while (month <= 12) and (fmtset.LongMonthNames[month] <> match.Groups.Item[3].Value) do inc(month); year := word.Parse(match.Groups.Item[4].Value); Writeln(FormatDateTime('yyyy-mm-dd', EncodeDate(year, month, day), fmtset)); end; Well there is a lot to improve, but you should get the idea. Share this post Link to post
ertank 27 Posted July 31, 2019 1 hour ago, Schokohase said: pattern := // '(' + string.Join('|', fmtset.LongDayNames) + ')' + // "dddd" ', ' + // ", " '(\d{2})' + // "dd" ' ' + // " " '(' + string.Join('|', fmtset.LongMonthNames) + ')' + // "mmmm" ' ' + // " " '(\d{4})'; // "yyyy" Well there is a lot to improve, but you should get the idea. Only thing that maybe missing is "ddd" and "mmm" aka ShortDayNames and ShortMonthNames above. I find RegEx powerful. Unfortunately, I am not familiar with it at all. Would you add these two possible patterns in your sample code, please? Share this post Link to post
Guest Posted July 31, 2019 Oh that is very complicated ... '(' + string.Join('|', fmtset.ShortDayNames) + ')' + // "ddd" '(' + string.Join('|', fmtset.ShortMonthNames) + ')' + // "mmm" ... not Share this post Link to post
ertank 27 Posted July 31, 2019 Seems like initial code I share is faster than RegEx after initial call. Moreover, RegEx is failing at certain formats at the moment which will probably make it slower in all cases when all features added. Timing test code: program Project2; {$APPTYPE CONSOLE} {$R *.res} uses System.SysUtils, uUtils.ParseExact, System.RegularExpressions, System.Diagnostics; function Test(const Value: string; const fmtset: TFormatSettings): TDateTime; var pattern: string; match: TMatch; day: word; month: word; year: word; begin pattern := // '(' + string.Join('|', fmtset.LongDayNames) + ')' + // "dddd" ', ' + // ", " '(\d{2})' + // "dd" ' ' + // " " '(' + string.Join('|', fmtset.LongMonthNames) + ')' + // "mmmm" ' ' + // " " '(\d{4})'; // "yyyy" match := TRegEx.match(Value, pattern); if not match.Success then raise Exception.Create('Invalid data'); day := word.Parse(match.Groups.Item[2].Value); month := 1; while (month <= 12) and (fmtset.LongMonthNames[month] <> match.Groups.Item[3].Value) do inc(month); year := word.Parse(match.Groups.Item[4].Value); try Result := EncodeDate(year, month, day); except Result := 0; end; end; const Date1 = 'Sunday, 22 September 2019'; Date2 = 'Monday, 20 January 2018'; Date3 = 'Sun 15 Sep 2019'; var ADate: TDateTime; AFormatSettings: TFormatSettings; Timing: TStopWatch; begin try AFormatSettings := TFormatSettings.Create('en-US'); WriteLn('Long code timings'); Timing := TSTopWatch.StartNew(); ADate := TDateTime.ParseExact(Date1, 'dddd, dd mmmm yyyy', AFormatSettings); Timing.Stop(); WriteLn(DateToStr(ADate), 'Time: ' + Timing.Elapsed); Timing := TStopwatch.StartNew(); ADate := TDateTime.ParseExact(Date2, 'dddd, dd mmmm yyyy', AFormatSettings); Timing.Stop(); WriteLn(DateToStr(ADate), 'Time: ' + Timing.Elapsed); Timing := TStopwatch.StartNew(); ADate := TDateTime.ParseExact(Date2, 'dddd, dd mmmm yyyy', AFormatSettings); Timing.Stop(); WriteLn(DateToStr(ADate), 'Time: ' + Timing.Elapsed); Timing := TStopwatch.StartNew(); ADate := TDateTime.ParseExact(Date3, 'ddd dd mmm yyyy', AFormatSettings); Timing.Stop(); WriteLn(DateToStr(ADate), 'Time: ' + Timing.Elapsed); WriteLn('RegEx code timings'); Timing := TSTopWatch.StartNew(); ADate := Test(Date1, AFormatSettings); Timing.Stop(); WriteLn(DateToStr(ADate), 'Time: ' + Timing.Elapsed); Timing := TSTopWatch.StartNew(); ADate := Test(Date2, AFormatSettings); Timing.Stop(); WriteLn(DateToStr(ADate), 'Time: ' + Timing.Elapsed); Timing := TSTopWatch.StartNew(); ADate := Test(Date2, AFormatSettings); Timing.Stop(); WriteLn(DateToStr(ADate), 'Time: ' + Timing.Elapsed); Timing := TSTopWatch.StartNew(); ADate := Test(Date3, AFormatSettings); Timing.Stop(); WriteLn(DateToStr(ADate), 'Time: ' + Timing.Elapsed); except on E: Exception do Writeln(E.ClassName, ': ', E.Message); end; ReadLn; end. My system output: Long code timings 22.09.2019Time: 00:00:00.0001696 20.01.2018Time: 00:00:00.0000132 20.01.2018Time: 00:00:00.0000157 15.09.2019Time: 00:00:00.0000134 RegEx code timings 22.09.2019Time: 00:00:00.0001281 20.01.2018Time: 00:00:00.0000404 20.01.2018Time: 00:00:00.0000255 Exception: Invalid data Share this post Link to post
Remy Lebeau 1391 Posted July 31, 2019 On 7/30/2019 at 1:49 AM, ertank said: I used to parse date string "Tue 17 Sep 2019" in an e-mail message using VarToDateTime() which served its purpose well. Now, format changed to "Sunday, 22 September 2019" and that function is not so helpful as before. Indy has StrInternetToDateTime() and GMTToLocalDateTime() functions in its IdGlobalProtocols unit which support both of those formats. Share this post Link to post