Ruby:
计算未来或过去的日期

How to: (如何操作：)

Ruby makes playing with dates quite friendly. Here’s how you can do it:

require 'date'

today = Date.today
# 将日期往未来增加5天
future_date = today + 5
# 将日期往过去减少10天
past_date = today - 10

puts "Today is: #{today}"
puts "Future Date: #{future_date}"
puts "Past Date: #{past_date}"

Sample output (示例输出):

Today is: 2023-04-12
Future Date: 2023-04-17
Past Date: 2023-04-02

Deep Dive (深入探索):

Before Ruby’s Date class, programmers had to calculate dates manually which was error-prone. Ruby’s standard library and gems like ‘activesupport’ provide robust methods for date manipulation, making tasks simpler and more readable.

Alternative ways to calculate date include Time and ActiveSupport::TimeWithZone for more complex time zone handling. Ruby’s Date performs well for date-specific manipulations.

细节：Ruby在内部使用格里高利历，对于处理不同文化和历史日期也有良好支持。还可以引入’time_difference’宝石来处理更复杂的日期和时间计算任务。

See Also (另请参阅):

• Ruby Documentation on Date: Date class - Ruby 3.1
• ActiveSupport Time Extensions: Active Support Core Extensions
• ’time_difference’ gem for complex calculations: time_difference on RubyGems