自定義日期範圍調查員

Question

聽起來有點愚蠢。但我正在嘗試使用yield關鍵字來創建自定義循環。

DateRange.new('2013-12-1', '2013-12-31').between do |date| 
    puts date 
end 

應導致

2013-12-1 
2013-12-2 
... 

DATERANGE類看起來像

class DateRange 
    attr_accessor :start_date, :end_date 

    def initialize(start_date, end_date) 
    @start_date = Date.parse(start_date.to_s) 
    @end_date = Date.parse(end_date.to_s) 
    end 

    def between(&block) 
    yield (start_date..end_date) 
    end  
end 

問題是自定義塊遍歷date_range

Answer 1

使用Range#each迭代Range對象，併產生每個項目。

require 'date' 

class DateRange 
    attr_accessor :start_date, :end_date 

    def initialize(start_date, end_date) 
    @start_date = Date.parse(start_date.to_s) 
    @end_date = Date.parse(end_date.to_s) 
    end 

    def between(&block) 
    (start_date..end_date).each { |x| 
     yield x 
    } 

    # OR 
    # (start_date..end_date).each &block   
    end  
end 


DateRange.new('2013-12-1', '2013-12-31').between do |date| 
    puts date 
end 

順便提一下，DateRange.new的第二個參數應該是String。 2013-12-31是1970。

Answer 2

我能夠跟這樣做

def between(&block) 
    (start_date..end_date).map do |date| 
    yield date 
    end 
end