String Iteration, Is it possible

Hi again guys,

I have now got a long list of code, that I would like to iterate - modifying the end of an App.Property key ( which I assume is a "string"),

The code is like this

}else if(Application.getValue("wptn") > 6) {
$.mWaypoints.add(Application.getValue("w7"));
$.mWaypoints.add(Application.getValue("lat7"));
$.mWaypoints.add(Application.getValue("long7"));
}else if(Application.getValue("wptn") > 7) {
$.mWaypoints.add(Application.getValue("w8"));
$.mWaypoints.add(Application.getValue("lat8"));
$.mWaypoints.add(Application.getValue("long8"));

where "wptn" is a number, and is the number of iterations I need to run, starting at 1

I need to be able to add the iteration number to the end of the partial getValue

Do you think this is possible?

for( var i=1; i < (Application.getValue("wptn")+1); i +=1) { 

$.mWaypoints.add(Application.getValue("w"+"i"));

}

flowstate over 5 years ago

What you're describing is string concatenation (joining two strings), not "string iteration".

The code you're looking for is:

"w" + i

In this case, i is implicitly converted to a string, then appended to "w".

This can easily be tested without actually using properties with code such as this:

        for (var i = 1; i <= 10; i++) {
           System.println("w" + i);
       }

This code will print:

w1
w2
w3
w4
w5
w6
w7
w8
w9
w10

If you want to use Application.getValue() as in your example above, you may need some guard code or a helper function to ensure that the return value is indeed a number.

For example, in the following code, if the "wptn" property doesn't exist for some reason, then the code will crash because you can't add null and 1.

for( var i=1; i < (Application.getValue("wptn")+1); i +=1) {

Furthermore, Application.getValue shouldn't be called on every iteration of the loop, as it could be expensive in terms of CPU and I/O. Since the value is not expected to change, you can call it once and store the result in a variable.

For example:

var wptn = Application.getValue("wptn");

if (wptn != null) {
    for (var i = 1; i <= wptn; i++) {
        var w = Application.getValue("w" + i);
        if (w != null) {
            $.mWaypoints.add(w);
        } else {
            // handle non-existent waypoint (System.println?)
        }
    }
} else {
    // handle non-existent waypoint count (System.println?)
}

Nick over 5 years ago in reply to flowstate

Thanks for your response, I learned more today!