So basically you are trying to deal with missing values in collections.
People working with R or Python data analytics framework made some
ways to work with specific data structures called dataframes
where you can have some missing values.
For example you may have a look here:
http://pandas.pydata.org/pandas-docs/stable/missing_data.html
On Wed, Dec 21, 2016 at 4:15 AM, stepharong <stepharong(a)free.fr> wrote:
Hi dear great OO designers
Here is a little challenges for your brainy souls :)
In Moose when we compute metrics it may happen than a tool (often external
to pharo) does not compute a metrics
and when we request it in moose we check and often we return a not so good
-1.
I'm trying to brainstorm on a solution
- first may be the simplest way is to not invoke a metrics when it is not
computed. But it means that we should know it and that we should have a
registration mechanism. After all this is probably the best solution.
- Second we were thinking to use exception but when we have multiple
entities missing one metrics.... I have serious doubts.
- Second I was thinking about having the following behavior
testCollect
| uarray collected |
uarray := UniformOrderedCollection new.
uarray add: 10.
uarray add: 20.
uarray add: (MissingValue discarding).
collected := uarray collect: [ :each | each ].
self assert: collected size equals: 2.
testDo
| res uarray |
uarray := UniformOrderedCollection new.
uarray add: 10.
uarray add: 20.
uarray add: (MissingValue discarding).
uarray add: 40.
res := 0.
uarray do: [ :each | res := res + each ].
self assert: res equals: 70.
testCollectDefaulting
| uarray collected |
uarray := UniformOrderedCollection new.
uarray add: 10.
uarray add: 20.
uarray add: (MissingValue default: 33).
collected := uarray collect: [ :each | each ].
self assert: collected size equals: 3.
self assert: collected third equals: 33
I basically started to implement
do: aBlock
"Refer to the comment in Collection|do:."
1 to: self size do:
[:index | (self at: index) toDo: aBlock on: self]
collect: aBlock
"Evaluate aBlock with each of the receiver's elements as the
argument.
Collect the resulting values into a collection like the receiver.
Answer
the new collection."
| newCollection |
newCollection := self species new.
self
do: [ :each | each toCollect: aBlock on: newCollection ].
^ newCollection
and
DiscardingValue >> toCollect: aBlock on: aCollection
"discard computation"
^ self
Object >> toCollect: aBlock on: aCollection
^ aCollection add: (aBlock value: self)
So I imagine that you see the design and I wanted to get your point of view.
--
Using Opera a kind of bad mail client but far better than thunderbird
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Serge Stinckwich
UCBN & UMI UMMISCO 209 (IRD/UPMC)
Every DSL ends up being Smalltalk
http://www.doesnotunderstand.org/