CODEWITHSUNDEEP
listscala
user3322141
user3322141

Reputation: 158

How to remove empty lists from list using scala?

I have following list structure -

List(List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List({"esx":"192.168.20.52","vm":" naa.60a9800042704577762b45634476337a ","datastore":"","vNic":"","portGroupVLan":"","vSwitch":"","physicalNic":"","lunName":"lun_30102014_101347)","writeIops":44998,"readIops":1635,"latency":47008,"serialNumber":"BpEwv+EcDv3z","usedSize":0,"totalSize":4,"availableSize":4,"throughput":null}, (), ()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List((), (), ()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List((), (), ()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List(()), List((), (), ()))

I want to remove all empty lists from above . I want output as -

List({"esx":"192.168.20.52","vm":" naa.60a9800042704577762b45634476337a ","datastore":"","vNic":"","portGroupVLan":"","vSwitch":"","physicalNic":"","lunName":"lun_30102014_101347)","writeIops":44998,"readIops":1635,"latency":47008,"serialNumber":"BpEwv+EcDv3z","usedSize":0,"totalSize":4,"availableSize":4,"throughput":null})

How do I get above output by using scala??

Upvotes: 0

Views: 3605

Answers (1)

Diego Martinoia
Diego Martinoia

Reputation: 4652

If your input is like that, i.e. you only have list(list(list())) depth, a double call to flatten will solve it.

val x = yourList
x.flatten.flatten

if your list has empty lists at various depths, you need to constantly flatten until you reach a fixed point:

val x = yourList
var y = x.flatten
var z = y.flatten
while (y != z) {
   y = z
   z = z.flatten
y

Hope that helps :)

Upvotes: 2

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