Chris Chris - 1 year ago 92
Swift Question

How to insert values into a multidimensional array in a loop swift

Couldnt find the answer to this.

I am trying to insert values into a multi dimensional array with something like this

_ = transportRef.observeEventType(.ChildAdded, withBlock: { (snapshotOne) in

self.yearList.insert(snapshotOne.key, atIndex: 0)

//print("snapshotone.key " + snapshotOne.key) // prints year

if let snapshotTwo = snapshotOne.children.allObjects as? [FIRDataSnapshot] {

for itemTwo in snapshotTwo {

self.monthList[self.counter].insert(itemTwo.key, atIndex: 0)

counter += 1

is in another loop outside this one. The thing is I receive an erro
Thread 1: EXC_BAD_INSTRUCTION (code=EXC_1386_INVOP, subcode=0x0)
and after playing around in Playground, I realise it is because my
monthList: [[String]] = [[]]
and therefore there isnt any array to insert or something like that. If I were to give it some init like
monthList = [["1"], ["2"]]
then I would be able to insert till
before it gives an error for

help? thanks

Answer Source

You need to provide the inner arrays to store the values into. You could do this by adding a while loop that adds more inner arrays until you have enough to insert to:

for item in itemsOne {
    while counter >= monthList.count {
    monthList[counter].insert(item.key, atIndex: 0)
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