Four different ways to iterate.

This topic contains 5 replies, has 4 voices, and was last updated by Jesse 2 years ago.

Viewing 6 posts - 1 through 6 (of 6 total)

Author

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April 1, 2017 at 3:01 pm #7674

Participant

This is not a request for help, but rather a snippet. I don’t know if there is a better place to post this but anyway here it is. Having a class that acts as a container of a list – exactly as the standard List<T> but not a list implementation, more as a wrapper of a list – you can iterate it’s contents with four different ways. My favorite option is “D” as you see below because you can essentially trick the API and handle it virtual as a list.

Updated Code: 08 Apr 2017

#Import "<std>"
 
Using std..

Class Collection<T>
	
	' Option A
	Field Items := New List<T>
	
	' Option B
	Method ToArray:T[]()
		Return Items.ToArray()
	End
	
	' Option C
	Method All:List<T>.Iterator()
		Return New List<T>.Iterator(Items, Items.FirstNode())
	End
	
	' Option D
	Operator To<C>:List<C>()
		Return Items
	End
End








Global Collection_:Collection<Int>

Function GenerateCollection(quantity:Int)
	Collection_ = New Collection<Int>
	For Local i := 1 To quantity
		Collection_.Items.Add(Cast<Int>(Rnd(0, 100)))
	Next
	Print("Created: " + Collection_.Items.Count() + " items.")
End



Function TestA()
	' A
	' print the items based on list iteration
	For Local i := Eachin Collection_.Items
		'Print("A: " + i)
	Next
End

Function TestB()
	' B
	' print the items based on the array overload method
	For Local i := Eachin Collection_.ToArray()
		'Print("B: " + i)
	Next
End
	
Function TestC()
	' C
	' print the items based on iterator
	For Local i := Eachin Collection_
		'Print("C: " + i)
	Next
End

Function TestD()
	' D
	' print the items based on cast
	For Local i := Eachin Cast<List<Int>>(Collection_)
		'Print("D: " + i)
	Next
End




Class Benchmark Abstract
	Private
	Global TimeStart:Int
	Global TimeEnd:Int
	Global TimeResult:Int

	Public
	Function Start()
		TimeStart = Millisecs()
		TimeEnd	= 0
	End

	Function Stop()
		TimeEnd = Millisecs()
		TimeResult = TimeEnd - TimeStart
	End

	Function PrintResult()
		Print("Time Elapsed: " + TimeResult)
	End
End




Function Main()
	GenerateCollection(1000000)


	Print("Starting Test A")
	Benchmark.Start()
	TestA()
	Benchmark.Stop()
	Benchmark.PrintResult()


	Print("Starting Test B")
	Benchmark.Start()
	TestB()
	Benchmark.Stop()
	Benchmark.PrintResult()

	
	Print("Starting Test C")
	Benchmark.Start()
	TestC()
	Benchmark.Stop()
	Benchmark.PrintResult()
	

	Print("Starting Test D")
	Benchmark.Start()
	TestD()
	Benchmark.Stop()
	Benchmark.PrintResult()

End

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#Import "<std>"

Using std..

Class Collection<T>

' Option A

Field Items := New List<T>

' Option B

Method ToArray:T[]()

Return Items.ToArray()

End

' Option C

Method All:List<T>.Iterator()

Return New List<T>.Iterator(Items, Items.FirstNode())

End

' Option D

Operator To<C>:List<C>()

Return Items

End

Global Collection_:Collection<Int>

Function GenerateCollection(quantity:Int)

Collection_ = New Collection<Int>

For Local i := 1 To quantity

Collection_.Items.Add(Cast<Int>(Rnd(0, 100)))

Print("Created: " + Collection_.Items.Count() + " items.")

End

Function TestA()

' A

' print the items based on list iteration

For Local i := Eachin Collection_.Items

'Print("A: " + i)

End

Function TestB()

' B

' print the items based on the array overload method

For Local i := Eachin Collection_.ToArray()

'Print("B: " + i)

End

Function TestC()

' C

' print the items based on iterator

For Local i := Eachin Collection_

'Print("C: " + i)

End

Function TestD()

' D

' print the items based on cast

For Local i := Eachin Cast<List<Int>>(Collection_)

'Print("D: " + i)

End

Class Benchmark Abstract

Private

Global TimeStart:Int

Global TimeEnd:Int

Global TimeResult:Int

Public

Function Start()

TimeStart = Millisecs()

TimeEnd = 0

End

Function Stop()

TimeEnd = Millisecs()

TimeResult = TimeEnd - TimeStart

End

Function PrintResult()

Print("Time Elapsed: " + TimeResult)

End

Function Main()

GenerateCollection(1000000)

Print("Starting Test A")

Benchmark.Start()

TestA()

Benchmark.Stop()

Benchmark.PrintResult()

Print("Starting Test B")

Benchmark.Start()

TestB()

Benchmark.Stop()

Benchmark.PrintResult()

Print("Starting Test C")

Benchmark.Start()

TestC()

Benchmark.Stop()

Benchmark.PrintResult()

Print("Starting Test D")

Benchmark.Start()

TestD()

Benchmark.Stop()

Benchmark.PrintResult()

End

April 8, 2017 at 3:27 am #7774

therevills

Participant

Does any one way have a speed advantage over the others?

April 8, 2017 at 10:06 am #7783

cocon

Participant

I did a measurement to see for real, time is in millisecs.

Created: 1000000 items.
Starting Test A
Time Elapsed: 160
Starting Test B
Time Elapsed: 64
Starting Test C
Time Elapsed: 158
Starting Test D
Time Elapsed: 157

Created: 1000000 items.

Starting Test A

Time Elapsed: 160

Starting Test B

Time Elapsed: 64

Starting Test C

Time Elapsed: 158

Starting Test D

Time Elapsed: 157

Some back story behind this test.
In real circumstances someone would go for the option A which is the most obvious and well understood concept. So this means that it’s end of story. ____ All of the other ways are most close to the concept of internal DSLs (I learnt about it these days) it’s about how you can utilize these techniques to create a very smooth API. ____ Option B converts your list to array, Option D proves how Monkey can use the To operator effectively to convert from List to List<B>. However option C is my favorite because it provides this smooth API transition, this way you can bypass internal class contents and let the object present itself according to how it is called (To operator in action).

Regarding the benchmarks
One striking thing to note in these benchmarks is that I never expected that array iteration (B) would be this fast. I had a subconscious fear for this due to this array conversion, (from the point I have a list ready to use – I see no reason to convert it to a list and iterate it) – however as it seems there is some compiler logic that make this happen. As far as I see this conversion happens only once, then the compiler will have to jump straight into array blocks. On the other hand option (A) as it involves objects and pointers, makes accessing the memory much more complicated.

April 8, 2017 at 11:42 am #7784

Jesse

Participant

here! test E is way faster.

[crayon-5cba8c036e315265052391 inline="true" ]
Using std..
 
Class Collection<T>
	
	' Option A
	Field Items := New List<T>
	
	' Option B
	Method ToArray:T[]()
		Return Items.ToArray()
	End
	
	' Option C
	Method All:List<T>.Iterator()
		Return New List<T>.Iterator(Items, Items.FirstNode())
	End
	
	' Option D
	Operator To<C>:List<C>()
		Return Items
	End
	
	'Option E
	Method ToNode:List<T>.Node()
		Return Items.FirstNode()
	End Method 
End
 
 
 
 
 
 
 
 
Global Collection_:Collection<Int>
 
Function GenerateCollection(quantity:Int)
	Collection_ = New Collection<Int>
	For Local i := 1 To quantity
		Collection_.Items.Add(Cast<Int>(Rnd(0, 100)))
	Next
	Print("Created: " + Collection_.Items.Count() + " items.")
End
 
 
 
Function TestA()
	' A
	' print the items based on list iteration
	For Local i := Eachin Collection_.Items
		'Print("A: " + i)
	Next
End
 
Function TestB()
	' B
	' print the items based on the array overload method
	For Local i := Eachin Collection_.ToArray()
		'Print("B: " + i)
	Next
End
	
Function TestC()
	' C
	' print the items based on iterator
	For Local i := Eachin Collection_
		'Print("C: " + i)
	Next
End
 
Function TestD()
	' D
	' print the items based on cast
	For Local i := Eachin Cast<List<Int>>(Collection_)
		'Print("D: " + i)
	Next
End
 
 Function TestE()
	 'E
 	 'Print the Items based on Node
 	 Local node := Collection_.ToNode()
 	 While node.Value
		'Print("E: " + i.Value)
	 	 node = node.Succ
	 Wend
End Function
 
Class Benchmark Abstract
	Private
	Global TimeStart:Int
	Global TimeEnd:Int
	Global TimeResult:Int
 
	Public
	Function Start()
		TimeStart = Millisecs()
		TimeEnd	= 0
	End
 
	Function Stop()
		TimeEnd = Millisecs()
		TimeResult = TimeEnd - TimeStart
	End
 
	Function PrintResult()
		Print("Time Elapsed: " + TimeResult)
	End
End
 
 
 
 
Function Main()
	Print "Processing ....."
	GenerateCollection(10000000)
  
	Print("Starting Test A")
	Benchmark.Start()
	TestA()
	Benchmark.Stop()
	Benchmark.PrintResult()
 
 
	Print("Starting Test B")
	Benchmark.Start()
	TestB()
	Benchmark.Stop()
	Benchmark.PrintResult()
 
	
	Print("Starting Test C")
	Benchmark.Start()
	TestC()
	Benchmark.Stop()
	Benchmark.PrintResult()
	
 
	Print("Starting Test D")
	Benchmark.Start()
	TestD()
	Benchmark.Stop()
	Benchmark.PrintResult()
	
	Print("Start Test E")
	Benchmark.Start()
	TestE()
	Benchmark.Stop()
	Benchmark.PrintResult()
 
End

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[crayon-5cba8c036e315265052391 inline="true" ]

Using std..

Class Collection<T>

' Option A

Field Items := New List<T>

' Option B

Method ToArray:T[]()

Return Items.ToArray()

End

' Option C

Method All:List<T>.Iterator()

Return New List<T>.Iterator(Items, Items.FirstNode())

End

' Option D

Operator To<C>:List<C>()

Return Items

End

'Option E

Method ToNode:List<T>.Node()

Return Items.FirstNode()

End Method

End

Global Collection_:Collection<Int>

Function GenerateCollection(quantity:Int)

Collection_ = New Collection<Int>

For Local i := 1 To quantity

Collection_.Items.Add(Cast<Int>(Rnd(0, 100)))

Print("Created: " + Collection_.Items.Count() + " items.")

End

Function TestA()

' A

' print the items based on list iteration

For Local i := Eachin Collection_.Items

'Print("A: " + i)

End

Function TestB()

' B

' print the items based on the array overload method

For Local i := Eachin Collection_.ToArray()

'Print("B: " + i)

End

Function TestC()

' C

' print the items based on iterator

For Local i := Eachin Collection_

'Print("C: " + i)

End

Function TestD()

' D

' print the items based on cast

For Local i := Eachin Cast<List<Int>>(Collection_)

'Print("D: " + i)

End

Function TestE()

'Print the Items based on Node

Local node := Collection_.ToNode()

While node.Value

'Print("E: " + i.Value)

node = node.Succ

Wend

End Function

Class Benchmark Abstract

Private

Global TimeStart:Int

Global TimeEnd:Int

Global TimeResult:Int

Public

Function Start()

TimeStart = Millisecs()

TimeEnd = 0

End

Function Stop()

TimeEnd = Millisecs()

TimeResult = TimeEnd - TimeStart

End

Function PrintResult()

Print("Time Elapsed: " + TimeResult)

End

Function Main()

Print "Processing ....."

GenerateCollection(10000000)

Print("Starting Test A")

Benchmark.Start()

TestA()

Benchmark.Stop()

Benchmark.PrintResult()

Print("Starting Test B")

Benchmark.Start()

TestB()

Benchmark.Stop()

Benchmark.PrintResult()

Print("Starting Test C")

Benchmark.Start()

TestC()

Benchmark.Stop()

Benchmark.PrintResult()

Print("Starting Test D")

Benchmark.Start()

TestD()

Benchmark.Stop()

Benchmark.PrintResult()

Print("Start Test E")

Benchmark.Start()

TestE()

Benchmark.Stop()

Benchmark.PrintResult()

End

[/crayon]

April 9, 2017 at 12:31 am #7801

impixi

Participant

@jesse

Your TestE function is wrong. Hint: it has something to do with your while condition.

EDIT: Okay here’s a solution (because Lists in MX2 are apparently circular):

[crayon-5cba8c03746b4058894228 inline="true" ]Function TestE()
	 'E
 	 Local firstNode := Collection_.ToNode()
 	 Local node := firstNode
 	 
 	 Repeat
 	 	'Do something useful here.
 	 	node = node.Succ
 	 Until node = firstNode
	 
End Function

[crayon-5cba8c03746b4058894228 inline="true" ]Function TestE()

Local firstNode := Collection_.ToNode()

Local node := firstNode

Repeat

'Do something useful here.

node = node.Succ

Until node = firstNode

End Function

[/crayon]

April 9, 2017 at 1:50 am #7803

Jesse

Participant

@impixi you are right. hahaha! At first I didn’t know why it wasn’t working. That’s because I have always used it with objects not integers or floats so I just assumed it was doing what it was supposed to. it works fine with objects not primitives. your solution solves it. I have to keep that in mind. unlikely I will use integers or floats in a list but who knows. Thanks!

It is still faster but not as I gave it credit for.

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Four different ways to iterate.

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