Map Tutorial Advanced

This is a follow up post to the following two other posts....

In this post I am going to talk about some more advanced ideas concepts in regards to using maps and lists together.

If you are reading this you are already aware of the power of using lists and maps together to create powerful DS scripts.

I'm going to cover HOW TO COMBINE A ZC MAP AND A ZC LIST TO CREATE MULTI-DIMENSIONAL ARRAYS( Think form records stored in script format).

In PHP it's very easy to create a multi-dimensional array (many map variables inside a big list) and encode

this into JSON... A PHP multidimensional associative array looks like this....

$client_array = array(

"client_address"=>array(

"street"=>"PO Box 1000",

"city"=>"Seattle",

"state"=>"WA",

"zip"=>"98122"

"contact_info"=>array(

"mobile"=>"555-1212",

"email"=>"john@acme.com"

)

);

In the above PHP example the $client_array would be a ZC Deluge Script list() where list.size() == 2.

the client_address and client_info arrays would be ZC Deluge Script map()'s

Stephen, Why would I want to make a multi-dimensional array in Zoho Creator?

1. Store records in script format to be added to a new application upon loading it for the first time. (instead of XML or a getURL() call)

2. Convert cumbersome XMLList()'s to an easy list/map format...

Replace _.executeXPath("/row/blah/blah/text()"); with a simple map.get("key");

NOTE: Try executing an XPath on an xmlList you called through a function! Your Xpath variable will come back null! This solves that problem/bug. (Let me know if you have solved this issue in the past.)

3. Store huge amounts of structured records data IN a variable to be looped through later.

Reason for coming up with this idea.

Recently I have been doing a lot of Zoho Creator API work with PHP & jQuery/Javascript coding using the JSON feed instead of XML... and I LOVE IT!

JSON is such a great data format and it's so easy to traverse over/iterate through the records in JSON..

Example: Traversing over JSON in Javascript

for (i = 0; i < length; i++) {
                    var name = suppliers[i].name;
                    var address = suppliers[i].address;
                    var zoho_id = suppliers[i].zoho_id;
                    });

Now back to Zoho Creator Maps! Zoho Creator Maps ARE VALID JSON when you output them to string..

But, at first I was completely unable to traverse over ZC Maps like you do in regular scripting (like the above JS example).

If you have noticed there is no "for each" option in the map manipulations on the script builder menu AND there isn't really a clear cut way to store key,value pairs in a regular list. (You could mess with indexes or create text deliminators and stuff but it's sort of a bad way of doing things.)

So I tried putting map() variables inside a list. This way I could store my maps inside a format that Zoho Creator permits looping.

If you try to put a map() variable inside a list this is what you get.......

Error at line : 13
Unsupported type given as argument

BUT! What if you convert your map variable to a STRING! Then your list is just holding text (text that is perfectly willing to be converted back into a map later AND is perfectly willing to be saved in a list!)

Let's look at an example of how we can create a MULTI-DIMENSIONAL ARRAY in Zoho Creator....

Creating a multi-dimensional array in Zoho Creator

list test.array_encode()

{

start_list = {"node1", "node2", "node3", "node4"};

end_list = List();

for each r in start_list

{

map = map();

map.put("field1", 1);

map.put("field2", 2);

map.put("feild3", 3);

map.put("field4", 4);

stringMap = map;

end_list.add(stringMap.toString());

}

test_list = list();

for each test in end_list

{

map = test.toMap();

test_list.add(map.get("field1"));

}

info test_list;

return end_list;

}

1. We created a function that returns a list

list test.array_encode()

{}

2. We created a "start_list" with node1 through node 4.

start_list = {"node1", "node2", "node3", "node4"};

The nodes are simply a list telling us how many iterations we are going to have. This could instead be a collection list of records or rows in an XML list perhaps.

3. Now we create an "end_list" this list will hold our key/value pairs (created by the map function).

end_list = List();

In our PHP example the end_list would be the $client_array variable and the "r" variable in the loop would be each

array inside the $client_array (separated by commas).

4. We create a new map, PUT our keys and values into the map, then convert it to a string!

map = map();

map.put("field1", 1);

map.put("field2", 2);

map.put("feild3", 3);

map.put("field4", 4);

stringMap = map;

end_list.add(stringMap.toString());

OUTPUT FROM HERE!

 
[{"field4":4,"feild3":3,"field1":1,"field2":2}, {"field4":4,"feild3":3,"field1":1,"field2":2}, {"field4":4,"feild3":3,"field1":1,"field2":2}, {"field4":4,"feild3":3,"field1":1,"field2":2}]

5. LET'S TEST IT!

test_list = list();

for each test in end_list

{

map = test.toMap();

test_list.add(map.get("field1"));

}

info test_list;

Here we create a "test_list" to grab our "values" from the array. We create a new map variable "map" then convert the map string BACK INTO A MAP. Then we just add the the map value to our list and "debug/Info" the test_list..

SURE ENOUGH THE "test_list" comes back with

1, 1, 1, 1

ISN'T THAT GREAT! If you start to think about it more you will see the similarities to the "for each record" function

but instead of using form field names to get your value you use the map's key value!

I hope you find great use out of this concept! Soon I will be posting some more ways to incorporate it into your DS scripts LIKE converting XML to ZC arrays without mapping hundreds of XPaths, storing many records inside ONE record, etc.

PLEASE let me know if you have ideas or suggestions on how to make this concept better. I am always open to ideas. If you have any questions you can go to my website, or post it here as a comment on the forum.

Stephen Rhyne

Owner

Rhyne Design