Date:         Tue, 18 Apr 2006 11:15:47 -0400
Reply-To:     Richard Ristow <wrristow@mindspring.com>
Sender:       "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:         Richard Ristow <wrristow@mindspring.com>
Subject:      Re: Nearest Match with Match Files
Comments: To: Brian Moore <bmoore@worldatwork.org>
In-Reply-To:  <6C01A852608309408AD59AFBFF5DD51A2364FF@aca_exchange.worlda
              twork.org>
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              x-avg-checked=avg-ok-1029339A

At 02:04 PM 4/17/2006, Brian Moore wrote:

>Is there a way to return a nearest match from a match table? I was
>thinking of numerical data and nearest being equal or next highest
>number on the lookup table (sorted ascending).

MATCH FILES, directly, can't do it. But it can be done by merging the
files with ADD FILES and computing the matching *exact* key for each
*approximate* key. See below, which is tested; this is SPSS draft
output. ("DATASET ACTIVATE" is SPSS 14 syntax. In earlier versions, one
would use scratch .SAV files instead of 'datasets', and they'd be "GET
FILE" instead.)

* ............................................... .
DATASET ACTIVATE KeyTable.
LIST.

List
|-----------------------------|---------------------------|
|Output Created               |18-APR-2006 11:07:51       |
|-----------------------------|---------------------------|
[KeyTable]

KEY Letter

   1 Alpha
   2 Beta
   3 Gamma
   5 Epsilon
   6 Eta

Number of cases read:  5    Number of cases listed:  5



DATASET ACTIVATE ToMatch.
LIST.

List
|-----------------------------|---------------------------|
|Output Created               |18-APR-2006 11:07:51       |
|-----------------------------|---------------------------|
[ToMatch]

  KEY ANIMAL

   .1 Aardvark
   .2 Anteater
  1.0 A.
  1.5 Bear
  1.7 Borogove
  2.0 B.
  3.0 C.
  3.2 Donkey
  3.5 Dromedary
  4.0 D.
  4.1 Eel
  4.6 Elephant
  5.0 E.

Number of cases read:  13    Number of cases listed:  13


ADD FILES
    /FILE = KeyTable /RENAME=(KEY=RoughKey)/IN=Key_Recd
    /FILE = *        /RENAME=(KEY=RoughKey)
    /BY RoughKey.
FORMATS RoughKey (F4.1)

* "nearest being equal or next highest number" requires  .
* descending order                                       .

RECODE Key_Recd (1=1)(ELSE=0).
SORT CASES BY RoughKey Key_Recd (D).

* Compute the corresponding exact-match key for each     .
* approximate key                                        .

NUMERIC KEY (F2).
LEAVE   KEY.
IF (Key_Recd EQ 1) KEY=RoughKey.
SELECT IF Key_Recd EQ 0.
SORT CASES By RoughKey.

LIST KEY RoughKey Animal.

List
|-----------------------------|---------------------------|
|Output Created               |18-APR-2006 11:07:52       |
|-----------------------------|---------------------------|
[ToMatch]

KEY RoughKey ANIMAL

   1     .1   Aardvark
   1     .2   Anteater
   1    1.0   A.
   2    1.5   Bear
   2    1.7   Borogove
   2    2.0   B.
   3    3.0   C.
   5    3.2   Donkey
   5    3.5   Dromedary
   5    4.0   D.
   5    4.1   Eel
   5    4.6   Elephant
   5    5.0   E.

Number of cases read:  13    Number of cases listed:  13


* Now, match, using the computed exact key               .

MATCH FILES
    /TABLE= KeyTable
    /FILE = *
    /BY Key
    /KEEP = Key RoughKey Letter Animal.
LIST.

List
|-----------------------------|---------------------------|
|Output Created               |18-APR-2006 11:07:52       |
|-----------------------------|---------------------------|
[ToMatch]

KEY RoughKey Letter   ANIMAL

   1     .1   Alpha    Aardvark
   1     .2   Alpha    Anteater
   1    1.0   Alpha    A.
   2    1.5   Beta     Bear
   2    1.7   Beta     Borogove
   2    2.0   Beta     B.
   3    3.0   Gamma    C.
   5    3.2   Epsilon  Donkey
   5    3.5   Epsilon  Dromedary
   5    4.0   Epsilon  D.
   5    4.1   Epsilon  Eel
   5    4.6   Epsilon  Elephant
   5    5.0   Epsilon  E.

Number of cases read:  13    Number of cases listed:  13






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