How to count elements from list if specific key present in list using scala? -

How to count elements from list if specific key present in list using scala? -

i have next list construction -

"disks" : [ { "name" : "a", "memberno" :1 }, { "name" : "b", "memberno" :2 }, { "name" : "c", "memberno" :3 }, { "name" : "d", } ]

i have many elements in list , want check 'memberno', if exists want count of list elements.

e.g. here count 3

how check if key exists , count of elements list using scala??

first create class represent input data

case class disk (name : string, memberno : string)

next load info repository (or other datasource)

val disks: list[disk] = ...

and count

disks.count(d => option(d.memberno).isdefined)

list scala