Finding a value in an array cache intersystems

Question

I'm hoping someone can help I'm trying to find a way to find a value in an array exists like the PHP in_array.

I have two variables PTOWN and ADDRESS. I want to find if the PTOWN is anywhere in the array?

Answer 1

Are you looking for if $data(ADDRESS("street 1")) write "found"?

Answer 2

Are you looking for PTOWN in the keys or the values of the nodes? If PTOWN might be found in the keys, you can use $ORDER to find the closest match to what you have. Let's say you have an array like this:

new PTOWN,Address,Array
set PTOWN="Paris"
set Address="Some address"
;
set Array("Paris")="123 Avenue Louis Pasteur"
set Array("Madrid")="434 Calle De Duermos"
set Array("Boston")="1522 Market Street"
;
if $ORDER(Array(PTOWN))=PTOWN d
    ...

$ORDER will return the key that matches your search term most closely and also comes after it in MUMPS' ordering system. So $ORDER(Array("Pa")) returns "Paris", $ORDER(Array("Mad")) returns "Madrid", and $ORDER(Array("Alameda")) returns "Boston" because "Boston" is the next thing after "Alameda" in the array.

You can use this to loop over all the keys in the array, as well:

new nodeName
set nodeName="" ; you have to pass $ORDER "" to get the first thing in the array
;
for  set nodeName=$ORDER(Array(nodeName)) quit:nodeName=""  d 
    ; $ORDER returns "" when you pass it the *last* key in the array, so we can quit this loop when we get that back
    ;
    if nodeName=PTOWN write Array(nodeName)

If PTOWN will be found in the values of the array, you'll have to use the loop method.

Answer 3

Assuming that PTOWN is '$needle' and ADDRESS is '$haystack' (as per in_array documentation), and without knowing the array format, the best you can do is something like:

in_array(needle,haystack)
    NEW idx,found,subAry
    SET found=0 ; If you want to return 0 instead of "" if not found
    ;
    FOR $ORDER(haystack(idx)) QUIT:idx="" DO  QUIT:found
    . ; If the format of the array is: array(<index>)=<value>
    . IF haystack(idx)=needle SET found=1 QUIT
    . ;
    . ; If the format of the array is: array(<key>)=<value>
    . ; Note: this type of search can be made a bit more efficient, but we're brute-forcing here
    . IF idx=haystack SET found=1 QUIT
    . ;
    . ; If you're using nested keys and values...this is NOT recommended since Cache doesn't really support recursion
    . MERGE subAry=haystack(idx)
    . SET found=$$in_array(needle,subAry)
    ;
    QUIT found

You'd call it like so:

...=$$in_array(PTOWN,.ADDRESS) ; Don't forget to pass by reference!