Need to parse string to Date safely

ruby-talk
1

I can have the date format as below :

"01/05/2014"
"02/04/2014 10:00"
"02/04/2014 10:00:23"

If I do only,

DateTime.strptime(date_string, "%d/%m/%Y %H:%M:%S") , I would get the
argument error, when *date_string* will not be having the format
"%d/%m/%Y %H:%M:%S".

What is the correct way to handle this using `Date::strptime`. I
wouldn't use `Date::parse`.

···

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2

How do you mean "safely"? Do you mean to accept strictly those 3 formats?

One way is to add the missing :00 on the string before parsing it, something like this:

     "12/03/2014 12:34".gsub!(/\b(\d{2}:\d{2})\b/, "\1:00")

Another way is to use rescue and run a list of valid matching patterns:

     require 'time'
     def parse_time(t)
       patterns ||= ["%d/%m/%Y %H:%M:%S", "%d/%m/%Y %H:%M", "%d/%m/%Y"]
       Time.strptime(t, patterns.shift)
     rescue ArgumentError => e
       patterns.any? ? retry : raise(e)
     end

Andrew Vit

···

On 14-03-18, 6:30, Arup Rakshit wrote:

I can have the date format as below :

"01/05/2014"
"02/04/2014 10:00"
"02/04/2014 10:00:23"

If I do only,

DateTime.strptime(date_string, "%d/%m/%Y %H:%M:%S") , I would get the
argument error, when *date_string* will not be having the format
"%d/%m/%Y %H:%M:%S".

What is the correct way to handle this using `Date::strptime`. I
wouldn't use `Date::parse`.

3

I've used nested rescue blocks before:

  begin
    DateTime.strptime(date_string, "%d/%m/%Y %H:%M:%S")
  rescue ArgumentError
    begin
      DateTime.strptime(date_string, "%d/%m/%Y %H:%M")
    rescue ArgumentError
      begin
        ...

It feels clunky but it works, and it can be made more elegant by turning it into a loop.

You could also use a case with regexes.
   
- A

···

On Mar 18, 2014, at 9:30 AM, Arup Rakshit <lists@ruby-forum.com> wrote:

I can have the date format as below :

"01/05/2014"
"02/04/2014 10:00"
"02/04/2014 10:00:23"

If I do only,

DateTime.strptime(date_string, "%d/%m/%Y %H:%M:%S") , I would get the
argument error, when *date_string* will not be having the format
"%d/%m/%Y %H:%M:%S".

What is the correct way to handle this using `Date::strptime`. I
wouldn't use `Date::parse`.

--
Posted via http://www.ruby-forum.com/\.