在 Ruby 中迭代数天

Question

I've tried the following:

def next_seven_days
  today = Date.today
  (today .. today + 7).each { |date| puts date } 
end 

But this just gives me the first and last date. I can't figure out how to get all the ones in between.

I was trying to follow the example here: http://www.whynotwiki.com/Ruby_/_Dates_and_times

Answer 1

I think you want something more like this:

def next_seven_days
  today = Date.today
  (today .. today + 7).inject { |init, date|  "#{init} #{date}" } 
end

In this case, the return value is a concatenated string containing all the dates.

Alternatively, if it's not a concatenated string you want, you could change the "#{init} #{date}" part of it.

As a side note, using puts in ruby on rails won't print to the web page. When you use <%= next_seven_days %> , the return value of that function is what will be printed to the page. The each function returns the range in parentheses.

Answer 2

Your code will definitely print all eight days to stdout. Your problem is that you're looking at the return value (which since each returns self will be (today.. today + 7) ).

Note that if you print to stdout inside an erb template, that won't cause the output to show up in the rendered template.

Answer 3

Your function RETURNS an enumeration designated by 2011-07-07..2011-07-14 which is displayed in your view, but your puts prints to STDOUT which is not going to be your view, but the console screen your server is running in =)

If you want your view to show a list of the seven days, you need to actually create the string that does that and RETURN that:)

def next_seven_days
  outputstr = ""
  today = Date.today
  (today..(today+7.days)).each { |date| outputstr += date.to_s }
  return outputstr 
end 

Answer 4

def next_seven_days
  today = Date.today
  (today..(today+7.days)).each { |date| puts date } 
end 

Answer 5

Use the "next" method

        def next_seven_days
          today= Date.today
          7.times do 
             puts today
             today=today.next
           end
        end