hi
here are the collection extensions we use in Moose.
I copied them to PharoTaskForces so that we can discuss and tweak the code if
wanted.
My favorite is
flatCollect:/flatCollectAsSet:
groupedBy:
There are really useful.
Stef
testFlatCollectArray
"self debug: #testFlatCollectArray"
self assert: ((#((1 2) (3 4) (5 3)) flatCollect: [ :each ]) = #(1 2 3 4
5 3)).
self assert: ((#((1 2) (2 3) (1 3 4)) flatCollect: [:each]) = #(1 2 2 3
1 3 4)).
self assert: ((#((1 2) (2 3) () ()) flatCollect: [:each]) = #(1 2 2
3)).
self assert: ((#((1 2) (2 3) (1 3 4)) flatCollect: [:each| Array with:
each])
= #(#(1 2) #(2 3) #(1 3 4))).
self assert: ((#((1 2) (2 3) (1 3 4)) flatCollect: [:each| Set with:
each])
= #(#(1 2) #(2 3) #(1 3 4))).
testFlatCollectSet
"self debug: #testFlatCollectSet"
self assert: ((#((1 2) (1 2) (1 3 4)) asSet flatCollect: [:each]) =
#(1 1 2 3 4) asSet).
self assert: ((#() asSet flatCollect: [:each]) = #() asSet).
self assert: ((#((1 2) () (1 3 4)) asSet flatCollect: [:each]) = #(1
1 2 3 4) asSet).
self assert: ((#((1 2) #((99)) (1 3 4)) asSet flatCollect: [:each])
= #(1 1 2 3 4 (99)) asSet).
self assert: ((#((1 2) #(()) (1 3 4)) asSet flatCollect: [:each])
= #(1 1 2 3 4 ()) asSet).
testCollectAsSet
"self debug: #testCollectAsSet"
self assert: ((#() collectAsSet: [:each | each odd]) = Set new).
self assert: (#(1 2 3 4 5 6) collectAsSet: [:each | each odd])
= (Set with: true with: false).
self assert: (#(1 3 5 7 9 11) collectAsSet: [:each | each odd])
= (Set with: true).
self assert: (#(1 2 3 4 5 4 3 2 1) collectAsSet: [:each | each]) = (1
to: 5) asSet.
testGroupedByArray
"self debug: #testGroupedByArray"
| res |
res := #(1 2 3 4 5) groupedBy: [:each | each odd].
self assert: (res at: true) = #(1 3 5).
self assert: (res at: false) = #(2 4)
Set>>flatCollect: aBlock
^self flatCollectAsSet: aBlock
Symbol>>value
"Allow this object to act as a ValueHolder on itself."
^self
OrderedCollection>>removeAtIndex: anIndex
"Remove the element of the collection at position anIndex. Answer the
object removed."
| obj |
obj := self at: anIndex.
self removeIndex: anIndex + firstIndex - 1.
^obj
Collection
==============================
collectAsSet: aBlock
"Evaluates aBlock for each element of the receiver and collects
the resulting values into a Set."
"This is an efficient shorthand for [ (self collect: aBlock) asSet ]."
"originally developed by a. kuhn and released under MIT."
^self inject: Set new into: [ :set :each |
set add: (aBlock value: each); yourself ].
copyEmpty: aSize
"Answer a copy of the receiver that contains no elements.
This method should be redefined in subclasses that add
instance variables, so that the state of those variables
is preserved"
^self class new: aSize
flatCollect: aBlock
"Evaluate aBlock for each of the receiver's elements and answer the
list of all resulting values flatten one level. Assumes that aBlock
returns some kind
of collection for each element. Equivalent to the lisp's mapcan"
"original written by a. Kuhn and released under MIT"
| stream |
self isEmpty ifTrue: [ ^ self copy ].
stream := (self species new: 0) nsWriteStream.
self do: [ :each | stream nextPutAll: (aBlock value: each) ].
^ stream contents
flatCollectAsSet: aBlock
"Evaluate aBlock for each of the receiver's elements and answer the
list of all resulting values flatten one level. Assumes that aBlock
returns some kind
of collection for each element. Equivalent to the lisp's mapcan"
"original written by a. Kuhn and released under MIT"
| set |
self isEmpty ifTrue: [^self copy ].
set := Set new.
self do: [ :each |
set addAll: (aBlock value: each) ].
^set
flatten
"Recursively collect each non-collection element of the receiver and
its descendant
collections. Please note, this implementation assumes that strings are
to be treated
as objects rather than as collection."
^self gather: [ :each ]
groupedBy: aBlock
"Return a dictionary whose keys are the result of evaluating aBlock for
all elements in
the collection, and the value for each key is the collection of
elements that evaluated
to that key. e.g.
#(1 2 3 4 5) groupedBy: [:each | each odd]
a Dictionary
true ---> #( 1 3 5)
false --> #(2 4)
originally developed by a. kuhn and released under MIT."
| result |
result := Dictionary new.
self do:
[:each | | key collection |
key := aBlock value: each.
collection := result at: key ifAbsentPut: [OrderedCollection
new].
collection add: each].
self species ~~ OrderedCollection ifTrue:
["Convert the result collections to be the right type.
Note that it should be safe to modify the dictionary
while iterating because we only replace values for existing
keys"
result keysAndValuesDo:
[:key :value | result at: key put: (self species
withAll: value)]].
^result
includesAll: aCollection
"Answer true if the receiver includes all elements of aCollection with
at
least as many occurrences as in aCollection. For a less strict
comparison
please refer to supersetOf: and its inverse subsetOf:."
^(aCollection isCollection) and: [
aCollection size <= self size and: [
aCollection allSatisfy: [ :each |
(aCollection occurrencesOf: each) <= (self
occurrencesOf: each) ]]]
nilSafeGroupedBy: aBlock
^ self groupedBy: [ :each |
| value |
value := aBlock value: each.
value ifNil: [ UndefinedObject ].
]
selectAsSet: aBlock
"Evaluate aBlock with each of the receiver's elements as the argument.
Collect into a new set, only those elements for which
aBlock evaluates to true. Answer the new collection."
| newSet |
newSet := Set new.
self do: [:each | (aBlock value: each) ifTrue: [newSet add: each]].
^newSet
shuffle
"Swaps the receiver's elements at random."
self shuffle: (self size * self size log) asInteger
sum: aSymbolOrBlock
^self
inject: 0
into: [:sum :each | sum + (aSymbolOrBlock value: each)]
shuffle: times
"Swaps random elements of the receiver."
| size random |
size := self size.
random := Random new.
times timesRepeat: [
self swap: (random next * size) floor + 1 with: (random next *
size) floor + 1
].
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