Sure, we could just use a
String to represent a date, like
"April 19, 1987". But Ruby has a built-in class that makes it much easier to work with dates:
Date class isn’t loaded into every Ruby program by default, so to use it we first need to say
(Usually we omit the parentheses around the string argument to the
require "date", we can create a new instance as usual with:
Date.new # => #<Date: -4712-01-01 ((0j,0s,0n),+0s,2299161j)>
By default, the new date is January 1st, of the year -4712 BCE! Interesting1, but not very helpful.
You can also pass
Date.new arguments to initialize with a specific year, month, and day:
Date.new(2001) #=> #<Date: 2001-01-01 ...> Date.new(2001,2,3) #=> #<Date: 2001-02-03 ...> Date.new(2001,2,-1) #=> #<Date: 2001-02-28 ...>
Date.today method returns an object initialized to the current date.
Date.today # => #<Date: 2019-04-16 ((2458590j,0s,0n),+0s,2299161j)>
Date.parse() method accepts a
String argument and tries to interpret it as a date, initializing a
Date.parse("2001-02-03") #=> #<Date: 2001-02-03 ...> Date.parse("20010203") #=> #<Date: 2001-02-03 ...> Date.parse("3rd Feb 2001") #=> #<Date: 2001-02-03 ...>
You can subtract two dates from one another, which will return the number of days between them. The return value class is a
Rational, which can be converted to a regular
number_of_days = Date.today - Date.parse("July 4, 1776") => (88674/1) days.to_i => 88674
Returns the day of the month (1-31).
held_on = Date.new(2001,2,3) held_on.mday #=> 3
true if the date is a Monday.
true if the date is a Tuesday.
true if the date is a Wednesday.
true if the date is a Thursday.
true if the date is a Friday.
true if the date is a Saturday.
true if the date is a Sunday.
Returns the day of week (0-6, Sunday is zero).
Date.new(2001,2,3).wday #=> 6