How can I get key's value from dictionary in Swift?

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[愿得一人]
[愿得一人] 2020-12-13 05:11

I have a Swift dictionary. I want to get my key\'s value. Object for key method is not working for me. How do you get the value for a dictionary\'s key?

This is my d

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  • 2020-12-13 06:12

    Use subscripting to access the value for a dictionary key. This will return an Optional:

    let apple: String? = companies["AAPL"]
    

    or

    if let apple = companies["AAPL"] {
        // ...
    }
    

    You can also enumerate over all of the keys and values:

    var companies = ["AAPL" : "Apple Inc", "GOOG" : "Google Inc", "AMZN" : "Amazon.com, Inc", "FB" : "Facebook Inc"]
    
    for (key, value) in companies {
        print("\(key) -> \(value)")
    }
    

    Or enumerate over all of the values:

    for value in Array(companies.values) {
        print("\(value)")
    }
    
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  • 2020-12-13 06:17

    From Apple Docs

    You can use subscript syntax to retrieve a value from the dictionary for a particular key. Because it is possible to request a key for which no value exists, a dictionary’s subscript returns an optional value of the dictionary’s value type. If the dictionary contains a value for the requested key, the subscript returns an optional value containing the existing value for that key. Otherwise, the subscript returns nil:

    https://developer.apple.com/documentation/swift/dictionary

    if let airportName = airports["DUB"] {
        print("The name of the airport is \(airportName).")
    } else {
        print("That airport is not in the airports dictionary.")
    }
    // prints "The name of the airport is Dublin Airport."
    
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