Dictionary

Dictionary

Init

Different types to initialize

let dict = [String: Int](/404)

let dict2: [String: Int] = [
		"Kautilya": 0,
		"Zeus": 1,
		"Sensehack": 2,
]

let dict3: [String: Int]?

var initProtocol = [String : Int](/404)
someProtocol["one"] = 1
someProtocol["two"] = 2

let someProtocol = [
    "one" : 1,
    "two" : 2
]

Access

Traversing

for (key, value) in dictionaryName {
		// Depending on types you would parse or type cast these data types while printing or utilizing.
    print("Key: \(key) & value: \(value)")
}

Complexity

Search

Searching time is always constant in Dictionary as they are hashed internally, so the key is accepted in any common hashable data type and Swift compiler internally generates a Hash value for it. So it’s easy to get those details.

Quirks

Thats the reason that Dictionary aren’t organized in a sorted manner.

Update

It’s also in constant Big O(1) time.

Applications

• Great for generating a hash map or keeping track of things in computer science.
• Different data types can be utilized.
• Great for real life enterprise scenarios where restful APIs returns a mix of primitive types in JSON data format.

convert Dictionary Values to Array

Could be replaced with compactMap { $0 } as well

let colors = colorsForColorScheme.values.flatMap { $0 }

Or

let colors = Array(dict.values)

Or

let colors = colorsForColorScheme.map { $0.1 }

References

SO

Tutorials Point

https://stackoverflow.com/questions/26988167/swift-dictionary-get-values-as-array