>Hi.
>There is an array aCache [x, 4]
>It is necessary to me to find the fourth array cell on 3 known values.
>If it would be in the table I has written
>LOCATE FOR x1=Search1 AND x2=Search2 AND x3=Search3
>IF FOUND ()
> lnResult = x4
>ENDIF
>But as it to make with array cells?

The best I can come up with off the top of my head:

LOCAL nRow, nNumRows
nNumRows = ALEN(aCache,1)
FOR nRow = 1 TO nNumRows
   IF (aCache[nRow,1] = Search1) AND ;
      (aCache[nRow,2] = Search2) AND ;
      (aCache[nRow,3] = Search3)
        EXIT
   ENDIF
ENDFOR
IF nRow > nNumRows
   *  Not found
ELSE
   *  nRow is the row we found that met the criteria
ENDIF