UDF: _Array1PullCommon

[blindwig]

I wrote a function that takes 2 arrays and returns an array containing all the elements common to both source arrays. It also strips these common elements out of the source arrays.

Sidenote: I'm calling my array UDFs _Array1*, because I deal mostly with 1-based arrays. Some of my functions accept 0-based array input, but always output 1-based arrays.

Here comes the code:

CODE

;===============================================================================

;

; Function Name: _Array1PullCommon()

; Description: Pulls all the common elements out of 2 given arrays and returns an array of these common elements.

; Parameter(s): $A1 and $A2 are 1-dimensional arrays, and $ArrayBase specifys weather they are 0- or 1-based

; Requirement(s):

; Return Value(s): Success: A 1-based array containung the elements common between arrays $a1 and $a2

; Failure: Empty String

; Note: Upon return, $a1 and $a2 will be 1-based, regardless of their base before the function call

; Note: Upon return, $a1 and $a2 will not longer contain the common elements

; Note: Upon return, $a1, $a2, and the returned array will all be sorted

; Author(s): Mike Ratzlaff <mike@ratzlaff.org>

; Revision: 20050622A

;

;===============================================================================

;

;Pulls the common elements out of $a1 and $a2, returns them in an array

;note: on return, all 3 arrays ($a1, $a2, and the returned array) are 1-based arrays

Func _Array1PullCommon(ByRef $a1, ByRef $a2, $ArrayBase = 1, $ProgressTitle = @ScriptName)

Dim $a1ndx, $a2ndx, $a1top, $a2top

;input check

If Not (IsArray($a1) And IsArray($a2)) Then

SetError(1)

Return ''

EndIf

;Setup

If $ArrayBase Then

$ArrayBase = 1

$a1Top = $a1[0]

$a2Top = $a2[0]

Else

$ArrayBase = 0

$a1Top = UBound($a1) - 1

$a2Top = UBound($a2) - 1

EndIf

If $a1top >= UBound($a1) or $a2top >= UBound($a2) Then

SetError(1)

Return ''

EndIf

$a1ndx = $ArrayBase

$a2ndx = $ArrayBase

Dim $a1new[$a1top + 1], $a2new[$a2top + 1]

If $a1top > $a2top Then

Dim $a3new[$a1top]

Else

Dim $a3new[$a2top]

EndIf

If $ProgressTitle <> '' Then ProgressOn($ProgressTitle, 'Comparing Lists...','',-1,-1,16)

If $ProgressTitle <> '' Then ProgressSet(16)

_ArraySort($a1, 0, $ArrayBase, $a1top)

If $ProgressTitle <> '' Then ProgressSet(33)

_ArraySort($a2, 0, $ArrayBase, $a2top)

If $ProgressTitle <> '' Then ProgressSet(50)

;compare arrays side-by-side

While $a1ndx <= $a1Top and $a2ndx <= $a2top

While $a1ndx <= $a1top And $a2ndx <= $a2top And $a1[$a1ndx] < $a2[$a2ndx]

$a1new[0] = $a1new[0] + 1

$a1new[$a1new[0]] = $a1[$a1ndx]

$a1ndx = $a1ndx + 1

WEnd

While $a1ndx <= $a1top And $a2ndx <= $a2top And $a1[$a1ndx] > $a2[$a2ndx]

$a2new[0] = $a2new[0] + 1

$a2new[$a2new[0]] = $a2[$a2ndx]

$a2ndx = $a2ndx + 1

WEnd

If $a1ndx <= $a1top And $a2ndx <= $a2top And $a1[$a1ndx] = $a2[$a2ndx] Then

$a3new[0] = $a3new[0] + 1

$a3new[$a3new[0]] = $a1[$a1ndx]

$a1ndx = $a1ndx + 1

$a2ndx = $a2ndx + 1

EndIf

If $ProgressTitle <> '' Then ProgressSet(50 + (($a1ndx + $a2ndx) * 50) / ($a1Top + $a2Top) )

WEnd

;finish out the arrays

While $a1ndx <= $a1Top

$a1new[0] = $a1new[0] + 1

$a1new[$a1new[0]] = $a1[$a1ndx]

$a1ndx = $a1ndx + 1

If $ProgressTitle <> '' Then ProgressSet(50 + (($a1ndx + $a2ndx) * 50) / ($a1Top + $a2Top) )

WEnd

While $a2ndx <= $a2Top

$a2new[0] = $a2new[0] + 1

$a2new[$a2new[0]] = $a2[$a2ndx]

$a2ndx = $a2ndx + 1

If $ProgressTitle <> '' Then ProgressSet(50 + (($a1ndx + $a2ndx) * 50) / ($a1Top + $a2Top) )

WEnd

;trim the new arrays

ReDim $a1new[$a1new[0] + 1]

ReDim $a2new[$a2new[0] + 1]

ReDim $a3new[$a3new[0] + 1]

If $ProgressTitle <> '' Then ProgressOff()

;return the new arrays

$a1 = $a1new

$a2 = $a2new

Return $a3new

EndFunc

Edited June 24, 2005 by blindwig

[blindwig]

Found sound bugs in my logic, fixed the code. Also added an optional progress meter. Edited the above post.

[jftuga]

How would you change this code so that it returned elements not contained in both?

For example:

$array1 contains 3456, 4567, 5678

$array2 contains 9999, 3456, 4567, 5678, 1111

I would want returned an array with just 9999 and 1111 in it.

Thanks,

-John

[blindwig]

How would you change this code so that it returned elements not contained in both?

For example:

$array1 contains 3456, 4567, 5678

$array2 contains 9999, 3456, 4567, 5678, 1111

I would want returned an array with just 9999 and 1111 in it.

Thanks,

-John

Sorry this reply is pretty late, but if you still need an answer:

Using code:

$a3=_Array1PullCommon($a1, $a2)

Now $a3 contains a list of common elements, and $a1 and $a2 contain the unique elements. So if you want a list of unique elements, just join or merge the two arrays:

$a4=_ArrayMerge($a1, $a2)

and now $a4 will contain the complete list of unique elements.

Do a search for an array merging routine, I'm sure that there are a few here somewhere...

[J_Y_C]

I am getting an error when using this function:

==> Array variable has incorrect number of subscripts or subscript dimension range exceeded.:

$a1new[$a1new[0]] = $a1[$a1ndx]

^ ERROR

before I spend too much time trying to wrap my head around why this is happening, do you know off the top of your head what it may be?