Ruby : Find a Date in a array of strings - ruby

Question

I am searching through an array of strings looking for a Date:
Is the method I'm using a good way to do it?
OR . . . is there a better alternative.
Perhaps a more "beautiful" way to do it?
query = {'Hvaða','mánaðardagur','er','í','dag?','Það','er','02.06.2011','hví','spyrðu?'}
def has_date(query)
date = nil
query.each do |q|
begin
date = Date.parse(q)
query.delete(q)
break
rescue
end
end
return date
end

Answer 1

Note that in Ruby we use square brackets [] for array literals (curly braces {} are for Hash literals).
Here is a solution that will find all dates in the array and return them as strings (thanks #steenslag):
require 'date'
arr = ['Hvaða', 'er', '02.06.2011', 'hví', '2011-01-01', '???']
dates = arr.select { |x| Date.parse(x) rescue nil }
dates # => ["02.06.2011", "2011-01-01"]

Answer 2

First you can try to validate the string, if it's a valid date format then you can parse it as a date:
query.each do |item|
if item =~ /^\d{2}([-\\\/.])\d{2}\1\d{4}$/ then
# coding
end
end

Answer 3

If you just want the first date and you want to be strict about a valid date:
arr = ['Hvaða', 'er', '02.06.2011', 'hví', '2011-01-01', '???']
date = arr.detect do |x| ## or find
d,m,y = x.split('.')
Date.valid_civil?(y.to_i, m.to_i, d.to_i)
end
p date #=> "02.06.2011"
(Date.parse is forgiving, it happily parses 02.13.2011)

Answer 4

If you want to parse more types of dates, use Chronic... I think it also has the side effect of not raising errors, just returns nil.
So if you want all valid dates found:
arr = ['Hvaða', 'er', '02.06.2011', 'hví', '2011-01-01', '???']
arr.collect {|a| Chronic.parse a}.compact
If you want the first:
arr.find {|a| Chronic.parse a}
and if you just want a true/false "is there a date here?"
arr.any? {|a| Chronic.parse a}