Regex question

ruby-talk
1

I have a file that contains the following contents:

sw_corner = 1000,-1000
ne_corner = -1000,1000

I want to read that file and figure out what the sw_corner and
ne_corner values are. Here's my following attempt, but it looks ugly.
How can I improve it?

sw_corner = map_data.scan(/sw_corner = ([-\d]+),\s*([-\d]+)/)[0]
ne_corner = map_data.scan(/ne_corner = ([-\d]+),\s*([-\d]+)/)[0]

Thanks,
Joe

2

(untested)

   h = {}
   map_data.each do |line|
     key, value = line.split %r/=/
     h[k.strip] = value.split(%r/,/).map{|n| Integer n}
   end
   p h['sw_corner']
   p h['nw_corner']

hth.

-a

···

On Thu, 4 Aug 2005, Joe Van Dyk wrote:

I have a file that contains the following contents:

sw_corner = 1000,-1000
ne_corner = -1000,1000

I want to read that file and figure out what the sw_corner and
ne_corner values are. Here's my following attempt, but it looks ugly.
How can I improve it?

sw_corner = map_data.scan(/sw_corner = ([-\d]+),\s*([-\d]+)/)[0]
ne_corner = map_data.scan(/ne_corner = ([-\d]+),\s*([-\d]+)/)[0]

Thanks,
Joe

--

email :: ara [dot] t [dot] howard [at] noaa [dot] gov
phone :: 303.497.6469
My religion is very simple. My religion is kindness.
--Tenzin Gyatso

===============================================================================

3

Hi --

I have a file that contains the following contents:

sw_corner = 1000,-1000
ne_corner = -1000,1000

I want to read that file and figure out what the sw_corner and
ne_corner values are. Here's my following attempt, but it looks ugly.
How can I improve it?

sw_corner = map_data.scan(/sw_corner = ([-\d]+),\s*([-\d]+)/)[0]
ne_corner = map_data.scan(/ne_corner = ([-\d]+),\s*([-\d]+)/)[0]

Here's one possibility, if you want them as integers:

require 'scanf'

map_data = <<EOM
sw_corner = 1000,-1000
ne_corner = -1000,1000
EOM

format = "%*s = %d,%d"

sw = map_data.scanf(format)
ne = map_data.scanf(format)

puts "sw is #{sw.inspect},ne is #{ne.inspect}"

David

···

On Thu, 4 Aug 2005, Joe Van Dyk wrote:

--

David A. Black
dblack@wobblini.net

4

Joe Van Dyk wrote:

I have a file that contains the following contents:

sw_corner = 1000,-1000
ne_corner = -1000,1000

I want to read that file and figure out what the sw_corner and
ne_corner values are. Here's my following attempt, but it looks ugly.
How can I improve it?

sw_corner = map_data.scan(/sw_corner = ([-\d]+),\s*([-\d]+)/)[0]
ne_corner = map_data.scan(/ne_corner = ([-\d]+),\s*([-\d]+)/)[0]

map_data = DATA.read

x = map_data.scan( /(sw|ne)_corner = (-?\d+),\s*(-?\d+)/ )
sw_corner = x.assoc("sw")[1,2]
ne_corner = x.assoc("ne")[1,2]

__END__
sw_corner = 1000,-1000
ne_corner = -1000,1000

5

Then there's always:

eval "filename" #:wink:

which will have exactly the right semantics in your case.

···

On 8/3/05, David A. Black <dblack@wobblini.net> wrote:

Hi --

On Thu, 4 Aug 2005, Joe Van Dyk wrote:

> I have a file that contains the following contents:
>
> sw_corner = 1000,-1000
> ne_corner = -1000,1000
>
> I want to read that file and figure out what the sw_corner and
> ne_corner values are. Here's my following attempt, but it looks ugly.
> How can I improve it?
>
> sw_corner = map_data.scan(/sw_corner = ([-\d]+),\s*([-\d]+)/)[0]
> ne_corner = map_data.scan(/ne_corner = ([-\d]+),\s*([-\d]+)/)[0]

Here's one possibility, if you want them as integers:

require 'scanf'

map_data = <<EOM
sw_corner = 1000,-1000
ne_corner = -1000,1000
EOM

format = "%*s = %d,%d"

sw = map_data.scanf(format)
ne = map_data.scanf(format)

puts "sw is #{sw.inspect},ne is #{ne.inspect}"

David

--

David A. Black
dblack@wobblini.net

6

Then there's always:

eval "filename" #:wink:

which will have exactly the right semantics in your case.

Ah... I was trying to do instance_eval. Why didn't that work?

···

On 8/3/05, Caleb Clausen <vikkous@gmail.com> wrote:

On 8/3/05, David A. Black <dblack@wobblini.net> wrote:
> Hi --
>
> On Thu, 4 Aug 2005, Joe Van Dyk wrote:
>
> > I have a file that contains the following contents:
> >
> > sw_corner = 1000,-1000
> > ne_corner = -1000,1000
> >
> > I want to read that file and figure out what the sw_corner and
> > ne_corner values are. Here's my following attempt, but it looks ugly.
> > How can I improve it?
> >
> > sw_corner = map_data.scan(/sw_corner = ([-\d]+),\s*([-\d]+)/)[0]
> > ne_corner = map_data.scan(/ne_corner = ([-\d]+),\s*([-\d]+)/)[0]
>
> Here's one possibility, if you want them as integers:
>
> require 'scanf'
>
> map_data = <<EOM
> sw_corner = 1000,-1000
> ne_corner = -1000,1000
> EOM
>
> format = "%*s = %d,%d"
>
> sw = map_data.scanf(format)
> ne = map_data.scanf(format)
>
> puts "sw is #{sw.inspect},ne is #{ne.inspect}"
>
>
> David
>
> --
>
>
> David A. Black
> dblack@wobblini.net
>
>

7

Hi --

Then there's always:

eval "filename" #:wink:

which will have exactly the right semantics in your case.

But variable scope problems:

$ cat corners.txt sw_corner = 1000,-1000
ne_corner = -1000,1000
$ ruby -e 'eval(File.read("corners.txt")); p sw_corner'
-e:1: undefined local variable or method `sw_corner' for main:Object
(NameError)

(Yes, you can pre-initialize them. It still seems fragile and has the
usual eval issues.)

David

···

On Thu, 4 Aug 2005, Caleb Clausen wrote:

On 8/3/05, David A. Black <dblack@wobblini.net> wrote:

Hi --

On Thu, 4 Aug 2005, Joe Van Dyk wrote:

I have a file that contains the following contents:

sw_corner = 1000,-1000
ne_corner = -1000,1000

I want to read that file and figure out what the sw_corner and
ne_corner values are. Here's my following attempt, but it looks ugly.
How can I improve it?

sw_corner = map_data.scan(/sw_corner = ([-\d]+),\s*([-\d]+)/)[0]
ne_corner = map_data.scan(/ne_corner = ([-\d]+),\s*([-\d]+)/)[0]

Here's one possibility, if you want them as integers:

require 'scanf'

map_data = <<EOM
sw_corner = 1000,-1000
ne_corner = -1000,1000
EOM

format = "%*s = %d,%d"

sw = map_data.scanf(format)
ne = map_data.scanf(format)

puts "sw is #{sw.inspect},ne is #{ne.inspect}"

David

--

David A. Black
dblack@wobblini.net

--
David A. Black
dblack@wobblini.net