Forum: Ruby fized size record from a string

Announcement (2017-05-07): www.ruby-forum.com is now read-only since I unfortunately do not have the time to support and maintain the forum any more. Please see rubyonrails.org/community and ruby-lang.org/en/community for other Rails- und Ruby-related community platforms.
Dffe86be8de621f205344af94b33995a?d=identicon&s=25 lucac81 (Guest)
on 2009-03-10 14:55
(Received via mailing list)
Hello, I'm new to Ruby, and I'm learning it with a project that also
involves rails...
I'm stuck with an apparently simple problem, I receive from a form a
String and I need to extend it to a fixed char number (it must be 16
chars with eventual trailing spaces)
I've tought to convert it to an array, it's easy but I don't know how
to extend it to the needed size.
Also I could add spaces to the string, but the again how can i control
how many I need to add?
Any hint on how I could do that?
Thank you very much
B33ea5c12d767bfd1253940a960274f5?d=identicon&s=25 Tim Hunter (timhunter)
on 2009-03-10 15:03
lucac81 wrote:
> Hello, I'm new to Ruby, and I'm learning it with a project that also
> involves rails...
> I'm stuck with an apparently simple problem, I receive from a form a
> String and I need to extend it to a fixed char number (it must be 16
> chars with eventual trailing spaces)

Look at the String#% method:

irb(main):003:0> "%-16s" % "123"
=> "123             "

This won't work if the original string is longer than 16, though. In
that case you just a copy of the original string.
49d522e24e66aafeb2a4547c6c5e260d?d=identicon&s=25 dkmd_nielsen (Guest)
on 2009-03-10 15:10
(Received via mailing list)
On Mar 10, 8:51 am, lucac81 <lcors...@gmail.com> wrote:
> Thank you very much
Simple, not very intelligent way could be

('string' + '-'*30)[0..16]
Dffe86be8de621f205344af94b33995a?d=identicon&s=25 lucac81 (Guest)
on 2009-03-10 15:11
(Received via mailing list)
On Mar 10, 2:51 pm, lucac81 <lcors...@gmail.com> wrote:
> Thank you very much
Uhmm I just found how to achieve this... using the ljust method of the
String class...

  str.ljust(integer, padstr=' ') => new_str

If integer is greater than the length of str, returns a new String of
length integer with str left justified and padded with padstr;
otherwise, returns str.

   "hello".ljust(4)            #=> "hello"
   "hello".ljust(20)           #=> "hello               "
   "hello".ljust(20, '1234')   #=> "hello123412341234123"

this solves my problem, and there is the rjust method that works fine
on the other side (I need that too)
Ef3aa7f7e577ea8cd620462724ddf73b?d=identicon&s=25 Rob Biedenharn (Guest)
on 2009-03-10 15:18
(Received via mailing list)
On Mar 10, 2009, at 9:53 AM, lucac81 wrote:

> Thank you very much
>

irb> str = "too short"
=> "too short"
irb> lng = "this one is big enough"
=> "this one is big enough"

With Kernel#sprintf (which String#% calls)
irb> "%-16.16s"%str
=> "too short       "
irb> "%-16.16s"%lng
=> "this one is big "

With String#ljust
irb> str.ljust(16)
=> "too short       "
irb> lng.ljust(16)
=> "this one is big enough"

With String#[] (not what you want for short ones)
irb> str[0,16]
=> "too short"
irb> lng[0,16]
=> "this one is big "

-Rob

Rob Biedenharn    http://agileconsultingllc.com
Rob@AgileConsultingLLC.com
This topic is locked and can not be replied to.