[lnkForumImage]
TotalShareware - Download Free Software
Confronta i prezzi di migliaia di prodotti.
Asp Forum
 Home | Login | Register | Search 


 

Forums >

comp.lang.ruby

Newbie question: Simple Ruby Date Question

mattscape

4/27/2005 10:07:00 PM

Hi everyone

I am playing around with ruby. And as a Java developer I wrote this
method to get me the weekdays of a month:
########
def weekdays(month)
current = Date.new(month.year,month.month,01)
result = Array.new
while (current.month == month.month)
if(current.wday != 0 && current.wday != 6)
result.push(current)
end
current += 1
end
return result
end
########

What would be a nice ruby way to write this?
4 Answers

Ryan Leavengood

4/27/2005 11:39:00 PM

0

Here is a slightly more Rubyish way to write this:

class Date
def weekdays
current = Date.new(year, month, 01)
result = []
while current.month == month
result << current if (1..5) === current.wday
current += 1
end
result
end
end

Now if you have a Date you can just call weekdays on it. I've taken out a
few unneeded parenthesis, but leaving them in wouldn't necessarily be an
unRuby way to write. Also the wday comparision now uses a Range and the
=== operator. This could also be written (1..5).member?(current.wday). In
addition I've decided to use << instead of push, and have also used the
syntax which puts the if at the end of the line (I'm not sure what the
official name is.) Lastly, there is no need for return if what you are
returning is the last line in the method.

Ryan Leavengood

mattscape wrote:
> Hi everyone
>
> I am playing around with ruby. And as a Java developer I wrote this
> method to get me the weekdays of a month:
> ########
> def weekdays(month)
> current = Date.new(month.year,month.month,01)
> result = Array.new
> while (current.month == month.month)
> if(current.wday != 0 && current.wday != 6)
> result.push(current)
> end
> current += 1
> end
> return result
> end
> ########
>
> What would be a nice ruby way to write this?

YANAGAWA Kazuhisa

4/28/2005 1:13:00 PM

0

In Message-Id: <1114639618.103794.222300@o13g2000cwo.googlegroups.com>
"mattscape" <matthias.luebken@gmail.com> writes:

> What would be a nice ruby way to write this?

Rather functional than rubyish though....

(Date.new(month.year, month.month, 1)..Date.new(month.year, month.month, -1)).select {|d| (1..5).include?(d.wday)}

is sufficient?

Date has instance method succ, so can generate Range, then we can use
Enumerable#select for filtering elements in the Range.


--
kjana@dm4lab.to April 28, 2005
Translators, traitors.

mattscape

4/28/2005 9:42:00 PM

0

Thanks !
I guess I like Ryans version better.
Mostly because I understand it ;-)

Brian Schröder

4/28/2005 10:14:00 PM

0

On 28/04/05, mattscape <matthias.luebken@gmail.com> wrote:
> Thanks !
> I guess I like Ryans version better.
> Mostly because I understand it ;-)
>
>

The version of Kazuhisa is not that hard to understand.
First:
(Date.new(month.year, month.month, 1)..Date.new(month.year, month.month, -1))
Is the range of days in the given month. (-1 is often used as index
for the last item, the same applies e.g. to Array and String).

Then he selects those elements from the range that have a weekday
between 1 and 5, that are all the days you wanted. The result is an
array of the weekdays of the month.

You will see that this reads a lot simpler than my english description
or your procedural code once you understood it.

Or break it in two lines then it is nearly english
days_of_the_month = (Date.new(month.year, month.month,
1)..Date.new(month.year, month.month, -1))
weekdays_of_month = days_of_the_month.select { | day | (1..5).include?day.wday }

best regards,

Brian

--
http://ruby.brian-sch...

multilingual _non rails_ ruby based vocabulary trainer:
http://www.vocabu... | http://www.g... | http://www.vok...