XML Considered Harmful

[Dennis Lee Bieber]

On Wed, 22 Sep 2021 09:52:59 -0500, "Michael F. Stemper"
<michael.stemper at gmail.com> declaimed the following:

>On 21/09/2021 19.30, Eli the Bearded wrote:
>> In comp.lang.python, Michael F. Stemper <michael.stemper at gmail.com> wrote:
>>> How does CSV handle hierarchical data? For instance, I have
>>> generators[1], each of which has a name, a fuel and one or more
>>> incremental heat rate curves. Each fuel has a name, UOM, heat content,
>>> and price. Each incremental cost curve has a name, and a series of
>>> ordered pairs (representing a piecewise linear curve).
>>>
>>> Can CSV files model this sort of situation?
>> 
	<SNIP> 
>> Yes, CSV files can model that. But it would not be my first choice of
>> data format. (Neither would JSON.) I'd probably use XML.
>
>Okay. 'Go not to the elves for counsel, for they will say both no
>and yes.' (I'm not actually surprised to find differences of opinion.)
>
	You'd have to include a "level" (and/or data type if multiple objects
can be at the same level) field (as the first field) in CSV which
identifies how to parse the rest of the CSV data (well, technically, the
CSV module has "parsed" it -- in terms of splitting at commas, handling
quoted strings (which may contain commas which are not split points, etc.).

1-generator, name
2-fuel, name, UOM, heat-content, price
2-curve, name
3-point, X, Y
3-point, X, Y
...
2-curve, name
3-point, X, Y
3-point, X, Y
...

	You extract objects at each level; if the level is the same or "lower"
(numerically -- higher in hierarchy) you attach the "previously" extracted
object to the parent object... Whether list or dictionary, or class
instance(s):

class Point():
	#Point may be overkill, easier to just use a tuple (X, Y)
	def __init__(self, X, Y):
		self.X = X
		self.Y = Y

class Curve():
	def __init__(self, name):
		self.name = name
		self.points = []

#use as aCurve.points.append(currentPoint)

class Fuel():
	def __init__(self, name, ..., price):
		self.name = name
		...
		self.price = price

class Generator():
	def __init__(self, name):
		self.name = name
		self.fuel = None
		self.curves = []

#aGenerator.fuel = currentCurve
#aGenerator.curves.append(currentCurve)



-- 
	Wulfraed                 Dennis Lee Bieber         AF6VN
	wlfraed at ix.netcom.com    http://wlfraed.microdiversity.freeddns.org/