Labelled text file parsing

ruby-talk
1

Hi. What I'd like to do is to take a file like so:

···

---
Apple
Color: Red
Peel: Yes
Has Core: Yes

Orange
Color: Orange
Peel: Yes
Has Core: No
---
and go through it, line by line, assigning the 'Apple' and 'Orange'
lines to a name attribute on different hashes, and then using the name
before the colons such as 'Color' and 'Peel' as keys for the respective
values.

I'm just asking for a bit of help and guidance, as I'm still not very
keen on using regular expressions that comfortably and all.

Thanks to anyone who helps!

2

An easier way to do this might be to use YAML (http://www.yaml.org) which is built into Ruby now.
Though, if you'd like this to be more of a project some very simple RegEx work and running through the text line by line wouldn't be too difficult.

···

On Dec 1, 2005, at 5:57 PM, CBlair1986 wrote:

Hi. What I'd like to do is to take a file like so:
---
Apple
Color: Red
Peel: Yes
Has Core: Yes

Orange
Color: Orange
Peel: Yes
Has Core: No
---
and go through it, line by line, assigning the 'Apple' and 'Orange'
lines to a name attribute on different hashes, and then using the name
before the colons such as 'Color' and 'Peel' as keys for the respective
values.

I'm just asking for a bit of help and guidance, as I'm still not very
keen on using regular expressions that comfortably and all.

Thanks to anyone who helps!

3

CBlair1986 wrote:

Hi. What I'd like to do is to take a file like so:
---
Apple
Color: Red
Peel: Yes
Has Core: Yes

Orange
Color: Orange
Peel: Yes
Has Core: No

How is this file created? It looks very much like YAML, and Ruby ships with a YAML parser, so if you have any say over the file format, make it valid YAML.

Something like this:

Apple :
   Color: Red
   Peel: Yes
   Has Core: Yes

Orange :
  Color: Orange
  Peel: Yes
  Has Core: No

James

···

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4

I'm in a terrible rush, but see if this code gets you going. Ask questions if you have them and I'll answer later...

James Edward Gray II

#!/usr/local/bin/ruby -w

require "pp"

data = Hash.new

DATA.each_line("") do |para|
   if para.sub!(/\A *(.+?) *\n/, "")
     data[$1] = Hash[*para.split("\n").map { |line| line.split(/:\s*/) }.flatten]
   end
end

pp data

__END__
Apple
Color: Red
Peel: Yes
Has Core: Yes

Orange
Color: Orange
Peel: Yes
Has Core: No

···

On Dec 1, 2005, at 7:57 PM, CBlair1986 wrote:

Hi. What I'd like to do is to take a file like so:
---
Apple
Color: Red
Peel: Yes
Has Core: Yes

Orange
Color: Orange
Peel: Yes
Has Core: No
---
and go through it, line by line, assigning the 'Apple' and 'Orange'
lines to a name attribute on different hashes, and then using the name
before the colons such as 'Color' and 'Peel' as keys for the respective
values.

I'm just asking for a bit of help and guidance, as I'm still not very
keen on using regular expressions that comfortably and all.

Thanks to anyone who helps!

5

CBlair1986 wrote:

Hi. What I'd like to do is to take a file like so:
---
Apple
Color: Red
Peel: Yes
Has Core: Yes

Orange
Color: Orange
Peel: Yes
Has Core: No
---
and go through it, line by line, assigning the 'Apple' and 'Orange'
lines to a name attribute on different hashes, and then using the name
before the colons such as 'Color' and 'Peel' as keys for the respective
values.

table = {}
ARGF.each { |line| line.strip!
  next if line == ""
  fields = line.split( /: +/ )
  if fields.size == 1
    $fruit = fields.first
    table[$fruit] = {}
  else
    table[$fruit][fields.first] = fields.last
  end
}

p table

6

William James wrote:

table = {}
ARGF.each { |line| line.strip!
  next if line == ""
  fields = line.split( /: +/ )
  if fields.size == 1
    $fruit = fields.first
    table[$fruit] = {}
  else
    table[$fruit][fields.first] = fields.last
  end
}

OK, I saw your $fruit rationale after removing $ :wink:

Here's a variation:

···

#---------------------------------------------------
table = {}; fruit = nil

IO.foreach('fruit.txt') do |line|
   k,v = line.strip.split(/: +/)
   k or next
   v and table[fruit][k] = v or table[fruit=k] = {}
end
#---------------------------------------------------

daz