How can I loop through each of the days of a given week in Ruby?

Question

I am defining monday and friday using the following:

@monday = Date.today.at_beginning_of_week

@friday = 5.days.since(@monday)

But I actually need, for any given day, to loop through Monday, Tuesday, Wednesday and take that date and put the output into a column.

<th>Monday</th>
<th>Tuesday</th>
etcetera

A given row, for example, would be:

<tr><td>method_with_arg(monday)</td><td>method_with_arg(tuesday)</td><td>method_with_arg(wednesday)</td></tr>

This is where value is a method that takes args date.

What's the cleanest way to do this?

Thanks.

Answer 1

def dates_week(d)
  (d.beginning_of_week...d.beginning_of_week+5).map{|a|
    "<td>#{a.strftime('%F')}</td>"
  }.join
end

dates_week Date.today
#=> "<td>2010-05-17</td><td>2010-05-18</td><td>2010-05-19</td><td>2010-05-20</td><td>2010-05-21</td>"

Instead of a.strftime you can call any other method receiving Date and returning string, such as mails_sent_on(a) etc. You can also use yield a there to pass your date-dependent logic using block:

def dates_week(d)
  (d.beginning_of_week...d.beginning_of_week+5).map{|a|
    yield a
  }.join
end

dates_week(Date.today) { |d|
  "<td>#{mails_sent_on(d)}</td>"
}

or, keeping strings out of dates_week method:

def dates_week(d)
  (d.beginning_of_week...d.beginning_of_week+5).map{|a|
    yield a
  }
end

dates_week(Date.today) { |d|
  mails_sent_on(d)
}.join(', ')

or whatever form you need.

Answer 2

I just use Plain Old Ruby Objects, but I think if you want to keep things DRY, you'd want to separate out the logic of weekdays from what you're using the weekdays for.

def dates_week(d)
  d.beginning_of_week...(d.beginning_of_week+5)
end

dates_week(Date.today).map {|a|
  "<td>#{a.strftime('%F')}</td>"
}.join

Answer 3

I'd go even one step further than Andrew and have it take a block:

def dates_week(d, delim)
  "<tr>" + (d.beginning_of_week...(d.beginning_of_week+5)).map do |day|
    "<#{delim}> #{yield(day)} </#{delim}>"
  end.join + "</tr>"
end

dates_week(Date.today, "th") {|d| d.strftime("%A")} # => <tr><th>Monday</th><th>Tuesday</th>...
dates_week(Date.today, "td") {|d| some_function(d)} #first row

Answer 4

The simplest solution I could think of would be:

monday = Date.today.at_beginning_of_week
days = []
7.times do |x|
     days << x.days.since(@monday)
end

days.each do |day|
     puts "<td>" + func(day) + "</td>"
end

That should do the trick