Can I make an array of arrays?

Im trying to create an array inside an array inside an array. Then use a UIPickerView with 3 components, each for the respective array. The reason I used arrays is because the data is organized like this:

var array1 = [
     "2"
[       "2"
           ["2.5","2.5"],
        "1-1/12"
           ["2.5","2.375"]],
     "3"
[       "2-1/2"
           ["3.375", "3.25"],
[       "2"
           ["3.375", "3"]]]

I've tried making dictionaries to call from (easier for UIPickerView) but the [(key:value)] combo won't work with tuples.

var dict: [(size: String, outlets: (outlet1: String, measure1: String, measure2: String))] = [
("2", ("1-1/2","2.5","2.375"))
]

func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 3
}

There's not much info about arrays inside arrays or dicts inside dicts.

The source data is from a chart that looks like this:

          --> outlet1 --> value1, value2
size1 --> --> outlet2 --> value1, value2
          --> outlet3 --> value1, value2

          --> outlet1 --> value1, value2
size2 --> 
          --> outlet2 --> value1, value2

Outlets can be the same String as size.