sort with list

[mediParticipant]

I have used ‘Compare’ below to sort a linked list in BlitzMax:

Monkey

Type MyType Field a:int Field b:int Field c:int Field d:int ... Method Compare:Int(otherObject:Object) Local t:MyType= MyType(otherObject) If Not t Return 1 EndIf Return a - t.a .. Or b - t.b .. Or c - t.c .. End Method End Type

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Type MyType   Field a:int Field b:int Field c:int Field d:int   ...   Method Compare:Int(otherObject:Object)    Local t:MyType= MyType(otherObject)     If Not t       Return 1    EndIf    Return a - t.a ..          Or b - t.b ..          Or c - t.c .. End Method   End Type

How to do this in Monkey 2?

[degacParticipant]

Hi

to place source code use the button ‘crayon’ in the text-box, it will open a proper ‘code editor’ where you can paste the source.

About list and ‘compare’ method follow this example

http://monkey2.monkey-x.com/forums/topic/a-clever-way-to-filter-lists/

[mediParticipant]

Thanks for the help!

How about this:

Monkey

Method Sort:Void( compareFunc:Int( T,T ) )

1	Method Sort:Void( compareFunc:Int( T,T ) )

in the manual, rather than a kind of IComapre? Will play with that for a while, then I will go back to the link.

[Mark SiblyKeymaster]

Here’s the basic idea:

Monkey

#Import "<std>" Using std.. Function Main() Local stack:=New Stack<Float>( 10 ) For Local i:=0 Until stack.Length stack[i]=Rnd() Next stack.Sort( Lambda:Int( x:Float,y:Float ) Return x<=>y End ) For Local t:=Eachin stack Print t Next End

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#Import "<std>"   Using std..   Function Main()   Local stack:=New Stack<Float>( 10 ) For Local i:=0 Until stack.Length stack[i]=Rnd() Next stack.Sort( Lambda:Int( x:Float,y:Float ) Return x<=>y End ) For Local t:=Eachin stack Print t Next End

The ‘lambda’ is an ‘inline’ funtion. You can also use a global function or method here, eg: stack.Sort( MyGlobalCompareFunc ).

The ‘<=>’ operator might look a bit weird, but it basically just returns an int value <0 if x<y, >0 if x>y and 0 if x=y. This is the default behavior if you just call Sort() with no comparison param.

[impixiParticipant]

Mark just beat me to it, about the ‘<=>’ operator. Anyway, here’s what I whipped up:

Monkey

[crayon-5cba152d94e1b669676159 inline="true" ]#Import "<std>" Using std.. Function Main() Local scores := New Stack<Score>() Local PrintAllScores := Lambda:Void(heading:String) Print heading + "~n" For Local score:= Eachin scores Print score.ToString() Next Print "~n~n" End scores.Push(New Score("Joe Blogs", 11)) scores.Push(New Score("Iron Man", 23)) scores.Push(New Score("Jane Doe", 12)) scores.Push(New Score("Dudeson", 10)) PrintAllScores("Before Sort") scores.Sort(False) PrintAllScores("After Sort") End Class Score Private Field _name:String Field _value:Int Public Method New(name:String, value:Int) Name = name Value = value End Property Name:String() Return _name Setter (name:String) _name = name End Property Value:Int() Return _value Setter (value:Int) _value = value End Operator<=>:Int(cmp:Score) Return Value<=>cmp.Value End Method ToString:String() Return Name + "~t~t" + Value End End

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[crayon-5cba152d94e1b669676159 inline="true" ]#Import "<std>"   Using std..   Function Main()   Local scores := New Stack<Score>()   Local PrintAllScores := Lambda:Void(heading:String) Print heading + "~n" For Local score:= Eachin scores Print score.ToString() Next Print "~n~n" End   scores.Push(New Score("Joe Blogs", 11)) scores.Push(New Score("Iron Man", 23)) scores.Push(New Score("Jane Doe", 12)) scores.Push(New Score("Dudeson", 10)) PrintAllScores("Before Sort") scores.Sort(False) PrintAllScores("After Sort") End   Class Score   Private Field _name:String Field _value:Int   Public Method New(name:String, value:Int) Name = name Value = value End   Property Name:String() Return _name Setter (name:String) _name = name End Property Value:Int() Return _value Setter (value:Int) _value = value End Operator<=>:Int(cmp:Score) Return Value<=>cmp.Value End   Method ToString:String() Return Name + "~t~t" + Value End   End

[/crayon]

[mediParticipant]

Thanks, so back to my sort and making life easier, I got this:

Monkey

#Import "<std>" Using std.. Struct Person Field name:String Field age:String Field height:String Field weight:String End Function ComparePersons:int(x:Person,y:Person) Return x.name<=>y.name End Function Function Main() Local per_list:= New List<Person> Local per:Person = New Person Print "---" per.name = "Aab" per.age = "45" per.height = "9" per.weight = "160" per_list.AddLast(per) per.name = "Elin" per.age = "45" per.height = "6" per.weight = "145" per_list.AddLast(per) per.name = "Sam" per.age = "75" per.height = "7" per.weight = "163" per_list.AddLast(per) per.name = "Aab" per.age = "45" per.height = "9" per.weight = "132" per_list.AddLast(per) per.name = "Sam" per.age = "45" per.height = "4" per.weight = "200" per_list.AddLast(per) per.name = "Elin" per.age = "15" per.height = "6" per.weight = "120" per_list.AddLast(per) per.name = "Aab" per.age = "15" per.height = "6" per.weight = "167" per_list.AddLast(per) per.name = "Sam" per.age = "75" per.height = "4" per.weight = "116" per_list.AddLast(per) For Local p := Eachin per_list Print p.name + "," + p.age + "," + p.height + "," + p.weight Next Local x:Person Local y:Person per_list.Sort(ComparePersons(x, y) ) per_list.Sort(true) Print "--" For Local t:=Eachin per_list Print t.name + "," + t.age + "," + t.height + "," + t.weight Next End

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#Import "<std>" Using std..   Struct Person   Field name:String   Field age:String   Field height:String   Field weight:String End   Function ComparePersons:int(x:Person,y:Person)     Return x.name<=>y.name End Function   Function Main()    Local per_list:= New List<Person> Local per:Person = New Person Print "---" per.name = "Aab" per.age = "45" per.height = "9" per.weight = "160" per_list.AddLast(per) per.name = "Elin" per.age = "45" per.height = "6" per.weight = "145" per_list.AddLast(per) per.name = "Sam" per.age = "75" per.height = "7" per.weight = "163" per_list.AddLast(per) per.name = "Aab" per.age = "45" per.height = "9" per.weight = "132" per_list.AddLast(per) per.name = "Sam" per.age = "45" per.height = "4" per.weight = "200" per_list.AddLast(per) per.name = "Elin" per.age = "15" per.height = "6" per.weight = "120" per_list.AddLast(per) per.name = "Aab" per.age = "15" per.height = "6" per.weight = "167" per_list.AddLast(per) per.name = "Sam" per.age = "75" per.height = "4" per.weight = "116" per_list.AddLast(per) For Local p := Eachin per_list     Print p.name + "," + p.age + "," + p.height + "," + p.weight Next Local x:Person Local y:Person per_list.Sort(ComparePersons(x, y) ) per_list.Sort(true) Print "--" For Local t:=Eachin per_list Print t.name + "," + t.age + "," + t.height + "," + t.weight Next End

Which prints:

Monkey

--- Aab,45,9,132 Elin,45,6,145 Sam,75,7,163 Aab,45,9,160 Sam,45,4,200 Elin,15,6,120 Aab,15,6,167 Sam,75,4,116 -- Aab,15,6,167 Aab,45,9,132 Aab,45,9,160 Elin,15,6,120 Elin,45,6,145 Sam,45,4,200 Sam,75,4,116 Sam,75,7,163

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--- Aab,45,9,132 Elin,45,6,145 Sam,75,7,163 Aab,45,9,160 Sam,45,4,200 Elin,15,6,120 Aab,15,6,167 Sam,75,4,116 -- Aab,15,6,167 Aab,45,9,132 Aab,45,9,160 Elin,15,6,120 Elin,45,6,145 Sam,45,4,200 Sam,75,4,116 Sam,75,7,163

Next stage?

a csvReader which I should figure out without readLine()

[Mark SiblyKeymaster]

…actually, this:

per_list.Sort(ComparePersons(x, y) )

looks a bit wrong. This actually calls the ‘ComparePersons’ function, but you probably wanted to pass the function to Sort() instead. The way to do that is simply:

per_list.Sort( ComparePersons )

Easy!

Since there is no ‘()’ after ComparePersons, the function is *not* actually called…

When you go:

per_list.Sort( ComparePersons(x,y) )

…this does actually call ComparePersons (which returns an int) and then passes the returned int as a parameter to Sort(), which is probably not what you meant.

Basically, ‘func()’ calls a function, while ‘func’ on its own does not. This takes a bit of getting used to but the main idea here is that it allows you to pass functions around just like they were ints or floats or arrays or strings or whatever!

[mediParticipant]

Thanks Mark, at least I tried

[Author]

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