Getting keys of multidimensional array (of `[String: [String: String]]`)

Question

I have a multidimensional array with structure [String: [String: String]]. I am able to reach the [String: String] bit with a for loop, but I couldn't figure out how to access to the main keys (this bit [String: [).

let items = snapshot.value as! [String: [String: String]]

for item in items.values {
    if let from = item["from"] {
         self.users.append(from)   // this works
    }
}

How can I reach the main id of this node?

The node looks like this:

- table
     - "1"
        - "from": "AA"
        - "to": "BB"
     - "2"
        - "from": "AA"
        - "to": "BB"

I am trying to get var array = ["1", "2", "3"]

Wilson XJ · Accepted Answer · 2016-06-07 06:07:09Z

3

use a Tuple will be clear try this :

let dict = ["1":["from":"aa","to":"bb"],"2":["from":"AA","to":"BB"]]

var array = [String]()
for (_ ,value) in dict{
    if let v = value["from"] {
        array.append(v)
    }
}
print(array)

update:

let keys = dict.keys.flatMap({$0})

print(keys)

edited Jun 7, 2016 at 6:07

answered Jun 7, 2016 at 6:01

Wilson XJ

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1 Comment

senty Over a year ago

I am trying have array as array = ["1","2"] etc. "from" bit is working fine. Do you have any suggestion?

Hayden McCabe · Accepted Answer · 2016-06-07 05:38:51Z

0

For arrays like that, where you have key->value pairs, you can access the key value as the element .0, and the value as element .1

Try this in a playground and see if it flies:

for firstLevel in tableArray {
    print(firstLevel.0)
    for innerLevel in firstLevel.1 {
        print(innerLevel.0)
        print(innerLevel.1)
    }
    print("\n")
}

answered Jun 7, 2016 at 5:38

Hayden McCabe

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1 Comment

senty Over a year ago

This also works but other answer is more right. Thanks

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