如何從當前日期計算過去的日期

Question

1. 返回日期爲「本週」

def this_week 
    if today == "wednesday" 
    return [date(sunday), ..., date(wednesday)]  
    end 
end 

1. 返回日期爲「上週」
一個數組的數組

def last_week 
    return [date(last.sunday), ..., date(last.saturday)] 
    end 

Answer 1

as a_date.wday給你the day of the week，你可以簡單地通過刪除它來找到星期日。從那裏，只需在陣列中添加星期日和下一天。就上個星期而言，僅僅是該陣列的每個元素減去7天。

require 'date' 
def this_week(today) 
    sunday = today - today.wday 
    week = [sunday] 
    (1..6).each do |wday| 
    week << sunday + wday 
    end 

    return week 
end 

def last_week(today) 
    return this_week(today).map { |elem| elem - 7} 
end