CODEWITHSUNDEEP
ruby-on-railsrubydate
Andrew
Andrew

Reputation: 238667

How to parse an abbreviated date in Ruby?

I am using Ruby 2.1 in a Rails 4.0.2 application. I need to convert a string into a valid Date object, but everything I try says it's an invalid date:

# in irb
date = 'Feb 9'
Date.strptime(date, '%m %-d')
# NoMethodError: undefined method `strptime' for Date:Class

# in Rails console
date = 'Feb 9'
Date.strptime(date, '%m %-d')
# ArgumentError: invalid date
#   from (irb):2:in `strptime'

date += ' ' + Time.now.year.to_s
Date.strptime(date, '%m %-d %Y')
# ArgumentError: invalid date

How can I parse a date in this abbreviated format?

Upvotes: 1

Views: 1006

Answers (3)

toro2k
toro2k

Reputation: 19228

The format string is wrong, it should be:

require 'date'
date = 'Feb 9'
Date.strptime(date, '%b %d').to_s
# => "2014-02-09"

%m would match a month number (1-12) while %b matches the abbreviated month name according to current locale. As the Ruby documentation says, available formats are documented in strptime(3) manual page.

Or use the Date.parse method:

Date.parse(date).to_s
# => "2014-02-09"

Update: I didn't notice it before, the - modifier to match the unpadded day number breaks strptime:

Date.strptime('9', '%-d').to_s
# ArgumentError: invalid date

Date.strptime('9', '%d').to_s
# => "2014-02-09"

Upvotes: 2

Dheer
Dheer

Reputation: 793

You can directly parse the date:

date = 'Feb 9'

Date.parse date

Upvotes: 1

Dave Newton
Dave Newton

Reputation: 160181

"Feb" is not a valid month number.

[1] pry(main)> date = 'Feb 9'
"Feb 9"
[2] pry(main)> Date.strptime(date, "%b %d")
Sun, 09 Feb 2014

E.g.,

%m - Month of the year, zero-padded (01..12)
        %_m  blank-padded ( 1..12)
        %-m  no-padded (1..12)
%B - The full month name (``January'')
        %^B  uppercased (``JANUARY'')
%b - The abbreviated month name (``Jan'')
        %^b  uppercased (``JAN'')
%h - Equivalent to %b

Upvotes: 4

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