Compare two lists

Blitz3D Forums/Blitz3D Programming/Compare two lists

CyberPackRat

(Posted 2012) [#1]

Wow, do I have a stupid question. This is like programming 101 but I am completely at a loss on how to do this the "right way".

I wish to compare two list and only want to count the number of similarities between them. Once a match item in both list is found, that same item will not be counted again, unless another occurrence is found in both list.

If "A" is in the first list 4 times and once in the second list, the total should be 1.

More examples:

List A            List B
-------            -------
A                   A
B                   B
C                   C
D                   B

Here there would be 3 matches


List A            List B
-------            -------
A                   C
B                   B
B                   B
C                   A

Here there would be 4 matches

This is my approach, it works but I don't think it looks very professional. Also, I would like this to be a function if possible.

Any ideas ?

Graphics 800,600,0,2

Dim list_a$(100)
Dim list_b$(100)
Dim list_match(100)

list_a$(1) = "A"
list_a$(2) = "B"
list_a$(3) = "C"
list_a$(4) = "D"

list_b$(1) = "D" 
list_b$(2) = "C" 
list_b$(3) = "D" 
list_b$(4) = "A" 

c = 0
	
For x = 1 To 4
	For y = 1 To 4
		If list_a$(x) = list_b$(y)			; Found a match
			If list_match(y) = 0			; Has it been counted?
				list_match(y) = 1			; If not, flag it
				Print list_a$(x)+" = "+list_b$(y)
				c = c + 1					; Increment counter
				Exit
			End If
		End If
	Next
Next

Print "Total Matches: " + c

WaitKey

Last edited 2012

CyberPackRat

(Posted 2012) [#2]

The Print statement in the loop is there for me to visually see when a match was found. It need not be there in the actual function / program.

I must apologize, while I am using Blitz3D but I probably have posted this in the Blitz 3D Beginners Area forum.

Last edited 2012

Matty

(Posted 2012) [#3]

Hello,

I've not tested this (not at a computer with blitz at present) but this should do the trick:

Type ListA

Field svalue$
Field matched%

End Type

Type ListB

Field svalue$
Field matched%

End Type

;set some values for the lists as an example


;using your example in your first post:

la.ListA = New ListA
la\svalue = "A"
la.ListA = New ListA
la\svalue = "B"
la.ListA = New ListA
la\svalue = "C"
la.ListA = New ListA
la\svalue = "D"

lb.ListB = New ListB
lb\svalue = "A"
lb.ListB = New ListB
lb\svalue = "B"
lb.ListB = New ListB
lb\svalue = "C"
lb.ListB = New ListB
lb\svalue = "B"

Function ListMatchCount()
Local count

For la.ListA = Each ListA
	For lb.ListB = Each ListB
		if lb\matched = false then
			if la\svalue = lb\svalue then 
				lb\matched = true 
				count = count + 1
			endif
		endif 		
	Next	
Next

Return count
End Function

CyberPackRat

(Posted 2012) [#4]

Didn't quite work. Made some adjustments and I believe it may be giving the proper results. Need to test some more before I know for sure.

Let you know after a bit. Thanks.

Matty

(Posted 2012) [#5]

Ahh..looking at it again an "exit" statement after the count increment should do it.