data aggregation and for loop in play+scala - json

Question

I'm very new to play! and scala and I'm trying to parse an array composed of json objects. I need to go through the array, count the number of specific occurrences in every object, add them up and pass them on to the html index. Here's what my controller would roughy look like:
object Application extends Controller {
def stringArray=<array of strings, each a JSValue>
var counter=0
for(i<-0 to stringArray.length){
counter+=(((Json.parse(stringArray(i))\"some_element").toString()).count(y=>y=="some_keyword"))
}
def index = Action {
Ok(views.html.index(counter))
}
}
But there's virtually no way to implement a for loop in the application controller. I've tried to pass on the array to index but other scala functions such as Json.parse and count seem to not be recognized the html template. What would be a possible workaround?

Answer 1

What about this?
object Application extends Controller {
val stringArray=<array of strings, each a JSValue>
def index = Action {
var counter = 0
for(s<-stringArray){
counter+=(((Json.parse(s)\"some_element").toString()).count(y=>y=="some_keyword"))
}
Ok(views.html.index(counter))
}
}
I haven't checked the inside part of the loop, but you seem to be confused about where to put the loop. Maybe this can be also rewritten as fold to have nicer code (for loops are generally considered not nice in Scala, as far as I understand ;) ). To use the functions in the templates, you may need to import them first. After the first line of template, where you declare the template function header, you can easily import stuff like for example: #import java.util.Date. Just make sure you import the correct class and you should be able to use the functions in templates as well.
And final note: 1 to 3 gives {1, 2, 3}, so you usually want 1 until array.length, as 1 until 3 gives {1, 2}. Usually you can use the for (element <- array) notation, which is easier to look at.