Forum: Ruby silly regex question

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Joe Van D. (Guest)
on 2006-01-04 00:24
(Received via mailing list)
Can someone help me make this code not suck?

require 'test/unit'

# EWWWWWWW
def process_string str
  result = Hash.new
  str.to_a.each do |line|
    line.scan(/important ([a-zA-Z0-9]+): /) do |key|
      result[key.first] = line
    end
  end
  result
end

class TestThis < Test::Unit::TestCase
  def example_string
    <<-END
    # comments
    important key1: some value's here
    important key2: some value's here
    important key3: some value's here
    important key4: some value's here

    other stuff we don't care about
    END
  end

  def test_process_string
    result = process_string example_string
    assert 4, result.size
    assert result.has_key?("key1")
    assert result.has_key?("key2")
    assert result.has_key?("key3")
    assert result.has_key?("key4")
  end
end
James G. (Guest)
on 2006-01-04 00:36
(Received via mailing list)
On Jan 3, 2006, at 4:22 PM, Joe Van D. wrote:

> Can someone help me make this code not suck?

I guess it depends on what you mean by that...

>   result
> end

def process_string str
   Hash[*str.scan(/^\s*(important ([a-zA-Z0-9]+): .+)
$/).flatten.reverse]
end

James Edward G. II
Joe Van D. (Guest)
on 2006-01-04 00:42
(Received via mailing list)
On 1/3/06, James Edward G. II <removed_email_address@domain.invalid> wrote:
> >   result = Hash.new
> $/).flatten.reverse]
> end

IMO, my version's more readable.  I'm going for readability here.
James G. (Guest)
on 2006-01-04 00:54
(Received via mailing list)
On Jan 3, 2006, at 4:41 PM, Joe Van D. wrote:

> IMO, my version's more readable.  I'm going for readability here.

def process_string str
   result = Hash.new
   str.scan(/^\s*(important ([a-zA-Z0-9]+): .+?)\s*$/) do |line, key|
     result[key] = line
   end
   result
end

# ... or ...

def process_string str
   str.inject(Hash.new) do |result, line|
     result[$1] = line if line =~ /^\s*important ([^:]+):/
     result
   end
end

James Edward G. II
Joe Van D. (Guest)
on 2006-01-04 01:17
(Received via mailing list)
Another silly regex question.

I have a regex that's getting to be more than 100 chars long.  How can
I split it up on multiple lines?

Joe
Wilson B. (Guest)
on 2006-01-04 01:26
(Received via mailing list)
On 1/3/06, Joe Van D. <removed_email_address@domain.invalid> wrote:
> Another silly regex question.
>
> I have a regex that's getting to be more than 100 chars long.  How can
> I split it up on multiple lines?
>
You can put the 'x' option on the end of the regular expression.
From the Pickaxe:
ExtendedMode: Complex regular expressions can be difficult to read. The
x option
allows you to insert spaces, newlines, and comments in the pattern to
make it more
readable.

e.g.
%r{some regex
with
multiple
lines
}x
Dan K. (Guest)
on 2006-01-04 01:29
(Received via mailing list)
Here's a rails example for validating email addresses.

  validates_format_of :login, :with => /
    ^[-^!$#%&'*+\/=?`{|}~.\w]+
    @[a-zA-Z0-9]([-a-zA-Z0-9]*[a-zA-Z0-9])*
    (\.[a-zA-Z0-9]([-a-zA-Z0-9]*[a-zA-Z0-9])*)+$/x,
    :message => "must be a valid email address",
    :on => :create
Joe Van D. (Guest)
on 2006-01-04 01:42
(Received via mailing list)
On 1/3/06, Wilson B. <removed_email_address@domain.invalid> wrote:
> make it more
> readable.
>
> e.g.
> %r{some regex
> with
> multiple
> lines
> }x

ah, nice.  Too bad vim doesn't highlight the comments.  :(
Chad P. (Guest)
on 2006-01-04 02:44
(Received via mailing list)
On Wed, Jan 04, 2006 at 07:51:55AM +0900, James Edward G. II wrote:
>
> def process_string str
>   str.inject(Hash.new) do |result, line|
>     result[$1] = line if line =~ /^\s*important ([^:]+):/
>     result
>   end
> end

Not that I'm the one that has to read it, but . . .
I like this one for readability.

--
Chad P. [ CCD CopyWrite | http://ccd.apotheon.org ]

unix virus: If you're using a unixlike OS, please forward
this to 20 others and erase your system partition.
Chad P. (Guest)
on 2006-01-04 02:44
(Received via mailing list)
On Wed, Jan 04, 2006 at 08:40:43AM +0900, Joe Van D. wrote:
>
> ah, nice.  Too bad vim doesn't highlight the comments.  :(

Have you tried setting this?:

  :syntax on

--
Chad P. [ CCD CopyWrite | http://ccd.apotheon.org ]

This sig for rent:  a Signify v1.14 production from
http://www.debian.org/
Devin M. (Guest)
on 2006-01-04 06:49
(Received via mailing list)
Joe Van D. wrote:

>    end
>  end
>  result
>end
>
>
def process_string str
  result = {}
  str.each_line do |line|
    important_stuff = line.split(/important\s+/,2)[1] or next
    key, value = important_stuff.split ':'
    result[key] = value
  end
  result
end
# More readable? I dunno... you be the judge. I might prefer it over:
# line, key, value = line.match /important\s+(\w+):\s*(.*)$/
# Though the latter is much more explicit.
Jeffrey M. (Guest)
on 2006-01-04 14:27
(Received via mailing list)
I was just perfecting my email address validator, mine allows multiple
email addresses in the email_address field:

validates_format_of :email_address, :with =>
/^\s*(?:(?:[^,@\s]+)@(?:(?:[-a-z0-9]+\.)+[a-z]{2,}\s*(,\s*|\z)))+$/i,
:allow_nil => true

It doesn't do as careful of an inspection as yours, although I've seen
some validations that are far more detailed. It'd be nice to have some
people contribute their suggestions for the ultimate email address
validation regular expression.

I also have this handy method in my class:

  def email_addresses
    self.email_address.split(',').map{|a| a.lstrip.rstrip }
  end

-Jeff
Brian Caswell (Guest)
on 2006-01-04 14:55
(Received via mailing list)
On Jan 4, 2006, at 7:25 AM, Jeffrey M. wrote:
> It doesn't do as careful of an inspection as yours, although I've seen
> some validations that are far more detailed. It'd be nice to have some
> people contribute their suggestions for the ultimate email address
> validation regular expression.

It already exists.  Go buy the first edition of Mastering Regular
Expressions.  There 11 page regex that matches emails.

Brian
Kevin B. (Guest)
on 2006-01-04 19:59
(Received via mailing list)
On Wednesday 04 January 2006 06:25, Jeffrey M. wrote:
> people contribute their suggestions for the ultimate email address
> validation regular expression.
>
> I also have this handy method in my class:
>
>   def email_addresses
>     self.email_address.split(',').map{|a| a.lstrip.rstrip }
>   end

Why do you lstrip and then rstrip?  Won't a simple strip work for you?
Jeffrey M. (Guest)
on 2006-01-04 23:07
(Received via mailing list)
> >   def email_addresses
> >     self.email_address.split(',').map{|a| a.lstrip.rstrip }
> >   end
>
> Why do you lstrip and then rstrip?  Won't a simple strip work for you?

YES! Nice to know! Hehe.

-Jeff
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