# Gen. Row objects from tab-delim text lines

**URL:** <https://www.ruby-forum.com/t/gen-row-objects-from-tab-delim-text-lines/97558>\
**Category:** Ruby\
**Created:** [July 7, 2006, 10:03pm UTC](https://www.ruby-forum.com/t/gen-row-objects-from-tab-delim-text-lines/97558 "2006-07-07T22:03:17Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\
**Post date:** [July 7, 2006, 10:03pm UTC](https://www.ruby-forum.com/t/gen-row-objects-from-tab-delim-text-lines/97558/1 "2006-07-07T22:03:17Z")

</div>

This is nothing ground-breaking, but I thought I’d share it anyway. It  
was a fun little exercise, and I’ve found it pretty useful.

RowParser.parse takes a String (or will read in an IO), assumes it’s  
\n- and \t-delimited, and that the first line is \t-delimited column  
headers. It generates a Row class with attributes named for the  
columns, and returns an array of populated Row objects. It does a bit  
of name munging, and allows for empty columns.

It’s been useful during this data conversion I’m working on – both SQL  
output and MS Word/Excel tables save to tab-delim text files easily.

Example: here’s a table of nutritional info for different beers (from  
[http://www.realbeer.com/edu/health/calories.php](http://www.realbeer.com/edu/health/calories.php)). I hope the tabs come  
out alright – notice that some of the columns are empty:

Brewery/Brand Beer Alcohol % Calories Carbs  
Amstel Light Amstel Light 3.5 95 5  
Alaskan Brewing Alaskan Amber 5  
Alaskan Brewing Alaskan Pale Ale 4.6  
Alaskan Brewing Alaskan Stout 5.7  
Alaskan Brewing Alaskan ESB 5  
Alaskan Brewing Alaskan Smoked Porter 6.1  
Alaskan Brewing Alaskan Winter Ale 6.2  
Anchor Anchor Steam 4.9 152  
Anchor Liberty Ale 6 188  
Anchor Anchor Porter 5.6 205

A bit of ruby:  
rp = RowParser.new  
data = rp.parse(File.open(“beer.txt”))  
data.each { |d|  
puts “#{d.beer}, #{d.calories}”  
}

The output:  
Amstel Light, 95  
Alaskan Amber,  
Alaskan Pale Ale,  
Alaskan Stout,  
Alaskan ESB,  
Alaskan Smoked Porter,  
Alaskan Winter Ale,  
Anchor Steam, 152  
Liberty Ale, 188  
Anchor Porter, 205

Here’s the source:

class String  
def conservative\_split(delim)  
str = self.to\_s  
bits = []  
while str.include? delim  
bits \<\< str.slice!(0…str.index(delim)).strip  
end  
bits \<\< str  
return bits  
end  
end

class RowParser  
attr\_reader :code

```
def parse(data)
	# If it's an IO, read it in. Else, assume it's a String.
	data = data.read if data.kind_of? IO
	data = data.split("\n") # Lines!

	# Create the Row class, based on the header columns
	headers = data.shift.split("\t") # First line is the column names
	headers.collect! do |h|
		h = h.slice!(0).chr.downcase + h # Downcase the first letter...
		h.gsub(/[^\w\d_]/, '') # ...and purge problematic punctuation.
	end

	symbs = headers.collect { |h| ":#{h}" }.join(', ') # For attr_reader
	args = headers.join(', ') # For the constructor
	attrs = headers.collect { |h| "@#{h}" }.join(', ') # For the attrs
	@code = <<CODE
		class Row
			attr_reader #{symbs}
			def initialize(#{args})
				#{attrs} = #{args}
			end
			def to_s
				[#{attrs}].join(', ')
			end
		end

```

CODE  
eval @code

```
	# Now, create a Row from each remaining line
	rows = []

	data.each { |line|
		line = line.conservative_split("\t")
		rows << Row.new(*line)
	}

	return rows
end

```

end

Hope it’s useful…  
Dan