Haπ day!

March 14^th, or should I say 3.14 is one of those fun days of the year where mathematicians can share private jokes. I am not categorizing myself as a mathematician, but I must admit I love maths and they fascinate me.

However, today is a special π day as it is in most of the world as we are 3/14/14 in the US and 14/3/14 in a lot of other countries around the world. An occasion to remind us about pi, this magimatical number. The number π is a mathematical constant, the ratio of a circle’s circumference to its diameter, approximately equal to 3.14159265358979323846264338327950 (ok, I must admit I only know by heart to 3.1415926).

Another good reason to remember about day formatters in Java. The easiest way to format a date is to use the SimpleDateFormat class. You simply specify a String pattern to format the day according to your needs. This is often a class I embed in my Java project:

public class DateUtils {

    public static String today() {
        Date date = new Date();
        SimpleDateFormat sdf = new SimpleDateFormat("EEEEE, MMMMM d, ''yy");
        return sdf.format(date);
    }

    public static String now() {
        Date date = new Date();
        SimpleDateFormat sdf = new SimpleDateFormat("h:mm a (z)");
        return sdf.format(date);
    }
}

The syntax from pattern String is rather easy to define (you can check it fully on the Java website), and copied here:

Char	Date or Time Component	Presentation	Examples
G	Era designator	Text	AD
y	Year	Year	1996; 96
Y	Week year	Year	2009; 09
M	Month in year	Month	July; Jul; 07
w	Week in year	Number	27
W	Week in month	Number	2
D	Day in year	Number	189
d	Day in month	Number	10
F	Day of week in month	Number	2
E	Day name in week	Text	Tuesday; Tue
u	Day number of week (1 = Monday, …, 7 = Sunday)	Number	1
a	Am/pm marker	Text	PM
H	Hour in day (0-23)	Number	0
k	Hour in day (1-24)	Number	24
K	Hour in am/pm (0-11)	Number	0
h	Hour in am/pm (1-12)	Number	12
m	Minute in hour	Number	30
s	Second in minute	Number	55
S	Millisecond	Number	978
z	Time zone	General time zone	Pacific Standard Time; PST; GMT-08:00
Z	Time zone	RFC 822 time zone	-0800
X	Time zone	ISO 8601 time zone	-08; -0800; -08:00

You use more or less characters to get more or less information:

• “EEEEE, MMMMM d, ”yy” is Friday, March 14, ’14.
• “h:mm a (z)” is 8:25 (EST).

Finally, remember that it will use your computer’s locale, so, if you are using a French local, you’ll get Vendredi, Mars 14, ’14. Which will sound weird to any French speaking person.