scatter across Array[Pair[]]

NicoBxl

Hi,

I've three String arrays that I put in a Array[Pair[]]. I would like to call a task on each of the elements of the new Array[Pair[]] as :

workflow test{
    Array[String] a
    Array[String] b
    Array[String] c
    Array[Pair[String,String,String]] x = zip(a,b,c) 
    scatter (y in x ) {
        call stuff{
            input :
                a=lane.a
                b=lane.b
                c=lane.c
        }
    }   
}

task stuff{
    String a
    String b
    String c
    command {
        echo ${a}" "${b}" "${c}
    }
}

In this example the lines in the call stuff{} will not work (e.g. a=lane.a)

Is there a way to do that ? Or maybe an other design than using Array[Pair[]] to group three arrays ?

Thank you

kshakir

A Pair only contains two members left and right. One can zip-a-zip though to create a structure with three elements.

For example:

workflow zip3 {
    Array[String] a = ["1a", "2a", "3a"]
    Array[String] b = ["1b", "2b", "3b"]
    Array[String] c = ["1c", "2c", "3c"]
    Array[Pair[String,String]] inner = zip(b,c)
    Array[Pair[String,Pair[String,String]]] outer = zip(a,inner)

    scatter (element in outer) {

        # Create a variable to access the "inner" pair
        Pair[String, String] right_pair = element.right

        call stuff {
            input:
                a = element.left,
                b = right_pair.left,
                c = right_pair.right
        }
    }
}

task stuff {
    String a
    String b
    String c
    command {
        echo ${a} ${b} ${c}
    }
    output { String out = read_string(stdout()) }
}