How to check if a string is a valid date

Question

I have a string: \"31-02-2010\" and want to check whether or not it is a valid date. What is the best way to do it?

I need a method which which returns

Answer 1

Date.parse not raised exception for this examples:

Date.parse("12!12*2012")
=> Thu, 12 Apr 2018

Date.parse("12!12&2012")
=> Thu, 12 Apr 2018

I prefer this solution:

Date.parse("12!12*2012".gsub(/[^\d,\.,\-]/, ''))
=> ArgumentError: invalid date

Date.parse("12-12-2012".gsub(/[^\d,\.,\-]/, ''))
=> Wed, 12 Dec 2012

Date.parse("12.12.2012".gsub(/[^\d,\.,\-]/, ''))
=> Wed, 12 Dec 2012

Answer 2

require 'date'
#new_date and old_date should be String
# Note we need a ()
def time_between(new_date, old_date)
  new_date = (Date.parse new_date rescue nil)
  old_date = (Date.parse old_date rescue nil)
  return nil if new_date.nil? || old_date.nil?
  (new_date - old_date).to_i
end

puts time_between(1,2).nil?
#=> true
puts time_between(Time.now.to_s,Time.now.to_s).nil?
#=> false

Answer 3

Similar to the solution by @ironsand, I prefer to create an overridden instance method on String:

class String
  def valid_datetime?
    to_datetime
    true
  rescue ArgumentError
    false
  end
end