Comments on: Ranges with dates (in Groovy)

By: peter

peter — Mon, 03 Dec 2007 10:19:01 +0000

With a little help from a colleague if figured out how to used Rails' date and time extensions when not running in Rails. Just load active_support:


irb(main):005:0> require 'rubygems'
=> true
irb(main):006:0> require 'active_support'
=> true

By: Using propertyMissing to enhance Date (in Groovy) at log4p

Using propertyMissing to enhance Date (in Groovy) at log4p — Sun, 02 Dec 2007 21:33:42 +0000

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By: railsguru

railsguru — Sun, 02 Dec 2007 20:58:08 +0000

Grr, <=> and succ that is..

By: railsguru

railsguru — Sun, 02 Dec 2007 20:57:23 +0000

Indeed! That’s the new thing I learned from this small excercise
As long as your class implements and succ you can use it in Range:

http://ruby-doc.org/core/classes/Range.html

By: peter

peter — Sun, 02 Dec 2007 20:48:14 +0000

But hey, interesting… Rails’ date object can actually be used in a range?

By: peter

peter — Sun, 02 Dec 2007 20:46:56 +0000

Aha, makes sense … I always tend to forget about the fact that Rails uses its’ own date and time classes…

By: railsguru

railsguru — Sun, 02 Dec 2007 20:41:50 +0000

The code is mend to be run in a Rails environment e.g. script/console. Anyway.. not trying to prove a point, just checked to see if the same could be done in Ruby

By: peter

peter — Sun, 02 Dec 2007 19:08:06 +0000

If you execute the code exactly as you pasted it; it wouldn't work. The Groovy code does work without any further 'import' or 'require'. If I execute:


irb> require 'date/format' 
irb> bd_peter = Date._parse('18-01-1979')
=> {:mon=>1, :year=>1979, :mday=>18}
irb> bd_peter = Date._parse('18-01-1979')
=> {:mon=>1, :year=>1979, :mday=>18}
irb> bd_daan = Date._parse('23-01-1980')
=> {:mon=>1, :year=>1980, :mday=>23}
irb> (bd_peter..bd_daan).each{|d| puts d if d.wday.zero?}
ArgumentError: bad value for range
        from (irb):18
        from :0

Did I import the wrong date?? There also is a slight difference in your ruby solution; which I could have used in my example... I build an array of the results and display it in a second each loop... could have been simpler:


sdf = new java.text.SimpleDateFormat("dd-MM-yyyy")

bd_daan = sdf.parse("23-01-1980")    
bd_peter = sdf.parse("18-01-1979") 

t = Calendar.instance  
all_sundays = (bd_peter..bd_daan).each{
	t.time = it; 
	if(t.get(Calendar.DAY_OF_WEEK) == Calendar.SUNDAY)
		println sdf.format(it)
}

Mind you, the use of a intermediate Calendar object is a bit overkill in this case... as is the use of the full blown Java date formatter. But the advantage is: full locale awareness when needed.

By: railsguru

railsguru — Sun, 02 Dec 2007 12:04:26 +0000

bd_daan = Date.parse(”23-01-1980″)
bd_peter = Date.parse(”18-01-1979″)

(bd_peter..bd_daan).each { |d| puts d if d.wday.zero? }