Delphi Basics : ReplaceDate command

DelphiBasics

ReplaceDate
Procedure

Change only the date part of a TDateTime variable

SysUtils unit

procedure ReplaceDate(var DateTimeVar TDateTime; const NewDateValue TDateTime);

Description

The ReplaceDate function updates the date part of a TDateTime variable DateTimeVar with the date part of another TDateTime value NewDateValue without affecting the time.

Related commands

DecodeDate		Extracts the year, month, day values from a TDateTime var.
DecodeDateTime		Breaks a TDateTime variable into its date/time parts
DecodeTime		Break a TDateTime value into individual time values
EncodeDate		Build a TDateTime value from year, month and day values
EncodeDateTime		Build a TDateTime value from day and time values
EncodeTime		Build a TDateTime value from hour, min, sec and msec values
RecodeDate		Change only the date part of a TDateTime variable
RecodeTime		Change only the time part of a TDateTime variable
ReplaceTime		Change only the time part of a TDateTime variable

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Example code : Change the date without changing the time

var
  myDateTime, newDate : TDateTime;

begin
  // Set the date to 29/10/2002 at 12:34:56
  myDateTime := EncodeDateTime(2002, 10, 29, 12, 34, 56, 0);
  ShowMessage('The starting date/time = '+DateTimeToStr(myDateTime));

  // Now change the date portion without touching the time
  newDate := EncodeDate(1957, 02, 18);
  ReplaceDate(myDateTime, newDate);
  ShowMessage('The new date/time = '+DateTimeToStr(myDateTime));
end;

Show full unit code

The starting date/time = 29/10/2002 12:34:56
The new date/time = 18/02/1957 12:34:56