Odd Date format conversion

[rockies1]

I have a file that I receive from another company. In it there are dates in this format:

2004001
or
2004294

The 2004 is the year, obviously, but the next 3 digits give me the month & day.

001 = 1/1
002 = 1/2
003 = 1/3
...
059 = 2/28
060 = 2/29 in a leap year, but 3/1 in a regular year
061 = 3/1 in a leap year, but 3/2 in a regular year

and so on.

I need to be able to convert the date I receive into a date that looks like this:
YYYYMMDD or 20041130

Any suggestions?

Thanks!

[CornedBee]

First, you slice off the year. Then you check if it's a leap year.

boolean isleap(int year) {
  return year % 4 == 0 && (year % 100 != 0 || year % 400 == 0);
}

Then you walk the months and substract their days from the day-in-year count until you reach a point where you have less or equal left than the next month has days. This gives you both the month and the day in it.


Edit: never mind the above. Just thought of a better way, since this is Java (I'm too fixed on C++).

Just slice the date into year and days.

java.util.Calendar c = new java.util.GregorianCalendar();
c.set(java.util.Calendar.YEAR, year);
c.set(java.util.Calendar.DAY_OF_YEAR, days);
java.text.DateFormat df = new java.text.SimpeDateFormat("yyyyMMdd");
String result = df.format(c.getTime());

[rockies1]

Thanks for the suggestion. This is what I ended up going with. Not real pretty, but it works.

public static boolean isLeap(int year) 
{
    return year % 4 == 0 && (year % 100 != 0 || year % 400 == 0);
}//End isLeap

public static String convertDate(String strDateIn)
{
    String strToReturn = "";
    String strYear = strDateIn.substring(0,4);
    boolean blnIsLeap = isLeap(Integer.parseInt(strYear));

    int intDays = Integer.parseInt(strDateIn.substring(4));

    if(blnIsLeap)
    {
	if(intDays < 32)
	{
	    //January
	    strToReturn = strYear + "01" + padString("" + intDays,2,"0",true);
	}
	else if(intDays < 61)
	{
	    //February
	    strToReturn = strYear + "02" + padString("" + (intDays-31),2,"0",true);
	}
	else if(intDays < 92)
	{
	    //March
	    strToReturn = strYear + "03" + padString("" + (intDays-60),2,"0",true);
	}
	else if(intDays < 122)
	{
	    //April
	    strToReturn = strYear + "04" + padString("" + (intDays-91),2,"0",true);
	}
	else if(intDays < 153)
	{
	    //May
	    strToReturn = strYear + "05" + padString("" + (intDays-121),2,"0",true);
	}
	else if(intDays < 183)
	{
	    //June
	    strToReturn = strYear + "06" + padString("" + (intDays-152),2,"0",true);
	}
	else if(intDays < 214)
	{
	    //July
	    strToReturn = strYear + "07" + padString("" + (intDays-182),2,"0",true);
	}
	else if(intDays < 245)
	{
	    //August
	    strToReturn = strYear + "08" + padString("" + (intDays-213),2,"0",true);
	}
	else if(intDays < 275)
	{
	    //September
	    strToReturn = strYear + "09" + padString("" + (intDays-244),2,"0",true);
	}
	else if(intDays < 306)
	{
	    //October
	    strToReturn = strYear + "10" + padString("" + (intDays-274),2,"0",true);
	}
	else if(intDays < 336)
	{
	    //November
	    strToReturn = strYear + "11" + padString("" + (intDays-305),2,"0",true);
	}
	else
	{
	    //December
	    strToReturn = strYear + "12" + padString("" + (intDays-335),2,"0",true);
	}
    }
    else
    {
	if(intDays < 32)
	{
	    //January
	    strToReturn = strYear + "01" + padString("" + intDays,2,"0",true);
	}
	else if(intDays < 60)
	{
	    //February
	    strToReturn = strYear + "02" + padString("" + (intDays-31),2,"0",true);
	}
	else if(intDays < 91)
	{
	    //March
	    strToReturn = strYear + "03" + padString("" + (intDays-59),2,"0",true);
	}
	else if(intDays < 121)
	{
	    //April
	    strToReturn = strYear + "04" + padString("" + (intDays-90),2,"0",true);
	}
	else if(intDays < 152)
	{
	    //May
	    strToReturn = strYear + "05" + padString("" + (intDays-120),2,"0",true);
	}
	else if(intDays < 182)
	{
	    //June
	    strToReturn = strYear + "06" + padString("" + (intDays-151),2,"0",true);
	}
	else if(intDays < 213)
	{
	    //July
	    strToReturn = strYear + "07" + padString("" + (intDays-181),2,"0",true);
	}
	else if(intDays < 244)
	{
	    //August
	    strToReturn = strYear + "08" + padString("" + (intDays-212),2,"0",true);
	}
	else if(intDays < 274)
	{
	    //September
	    strToReturn = strYear + "09" + padString("" + (intDays-243),2,"0",true);
	}
	else if(intDays < 305)
	{
	    //October
	    strToReturn = strYear + "10" + padString("" + (intDays-273),2,"0",true);
	}
	else if(intDays < 335)
	{
	    //November
	    strToReturn = strYear + "11" + padString("" + (intDays-304),2,"0",true);
	}
	else
	{
	    //December
	    strToReturn = strYear + "12" + padString("" + (intDays-334),2,"0",true);
	}
    }
    System.out.println(strDateIn + " = " + strToReturn);
    return strToReturn;
}//End convertDate

/******************************************************************************
   NAME:     padString
   PURPOSE:  Used to pad a string, either left or right, with whatever padding
			 character is passed in
   ACCEPTS:  String strDataIn - The string to pad
			 int intMaxLength - The length to pad to
			 String strPadWith - The string to pad with
			 boolean blnLeftPad - True to left pad, false to right pad
   RETURNS:  A String that has been padded appropriately.

   REVISIONS:
   Ver        Date        Author        Description
   ---------- ----------- ------------- ---------------------------------------
   1.0        20030917    merick01      Initial Creation of Method

******************************************************************************/
public static String padString(String strDataIn, int intMaxLength, String strPadWith, boolean blnLeftPad)
{
	String strToReturn = "";
	if (blnLeftPad == true)
	{
		while ((strToReturn.length() + strDataIn.length())<intMaxLength)
		{
			strToReturn = strToReturn + strPadWith;
		}
		strToReturn = strToReturn + strDataIn;
	}
	else
	{
		strToReturn = strToReturn + strDataIn;
		while (strToReturn.length()<intMaxLength)
		{
				strToReturn = strToReturn + strPadWith;
		}
	}
	return strToReturn;
}//End padString

[CornedBee]

Have you read the edit on my post? The stuff about GregorianCalendar? It's a far superior method.

[rockies1]

I have got to learn to refresh before posting.

I can't believe I spent all that time on so much code when this little bit did it.

Thank you SO much!