Count number of months using month names in ruby - ruby

Question

In ruby how can i count number of months between two months using their names
Examples:
Feb to Oct => 9
Dec to Mar => 4
Apr to Aug => 5
How can i achieve this ?

Answer 1

def months_between( start_month, end_month)
month_names = %w[ Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec ]
(12 + month_names.index( end_month ) - month_names.index( start_month ) ) % 12 + 1
end

Answer 2

You could define an array of 12 elements, containing your possible month names. Then, when you need to find the number of months between month1 and month2, you need to find their indexes, possibly using a hash, like this:
#let month1 and month2 be the values
array = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
hash = Hash[array.map.with_index.to_a] # => {"a"=>0, "b"=>1, "c"=>2}
#(hash[month2] + 12 - hash[month1]) % 12 should yield the desired result
However, the solution above does not deal with years. If month1 is 'Jan' and month2 is 'Feb', then the result will be 1, regardless of the year of month1 and the year of month2.
I am not fluent in Ruby, so my code might have errors in its syntax.

Answer 3

Use can use DateTime::strptime to get number represented the order of the month in a year. From there it should be easy
require 'date'
def distance(start_month, end_month)
distance = DateTime.strptime(end_month,"%b").month - DateTime.strptime(start_month,"%b").month + 1
distance < 0 ? distance + 12 : distance
end

Answer 4

If you have the month name then you can parse that month and get the sequence number of that month, like this:
require 'date'
month1 = Date.parse("Feb").month
month1 = Date.parse("Apr").month
Or You can use array of 12 month to find their sequence number.
And for counts between months:
result = ((month2 > month1) ? (month2 - month1) : (month1 - (month1 - month2)) + 1)
This will work for the sequence of the months. If the month1 id 'Dec' and month2 is 'Mar', then it will return count 4, not 9.