How can I calculate the day of the week of a date in ruby?

Question

How can I calculate the day of the week of a date in Ruby? For example, October 28 of 2010 is = Thursday

Answer 1

Date.today.strftime("%A")
=> "Wednesday"

Date.today.strftime("%A").downcase  
=> "wednesday"

Answer 2

Say i have date = Time.now.to_date then date.strftime("%A") will print name for the day of the week and to have just the number for the day of the week write date.wday.

Answer 3

Works out of the box with ruby without requiring:

Time.now.strftime("%A").downcase #=> "thursday"

Answer 4

Take a look at the Date class reference. Once you have a date object, you can simply do dateObj.strftime('%A') for the full day, or dateObj.strftime('%a') for the abbreviated day. You can also use dateObj.wday for the integer value of the day of the week, and use it as you see fit.

Answer 5

As @mway said, you can use date.strftime("%A") on any Date object to get the day of the week.

If you're lucky Date.parse might get you from String to day of the week in one go:

def weekday(date_string)
  Date.parse(date_string).strftime("%A")
end

This works for your test case:

weekday("October 28 of 2010") #=> "Thursday"

Answer 6

Quick, dirty and localization-friendly:

days = {0 => "Sunday",
1 => "Monday", 
2 => "Tuesday",
3 => "Wednesday",
4 => "Thursday",
5 => "Friday",
6 => "Saturday"}

puts "It's #{days[Time.now.wday]}"