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What is a dictionary in Swift?

Swift dictionary is an unordered collection of items. It stores elements in key/value pairs. Here, keys are unique identifiers that are associated with each value.

How do I read a dictionary in Swift?

Example 1 – Get Value in Dictionary using Key

In this example, we shall create a dictionary with initial values, and access the values from this dictionary using keys. var myDictionary:[String:Int] = [“Mohan”:75, “Raghu”:82, “John”:79] var mohanScore = myDictionary[“Mohan”] print(“value is: \(mohanScore!)”)

How do you create a dictionary in Swift?

What is array and dictionary in Swift?

Swift provides three primary collection types, known as arrays, sets, and dictionaries, for storing collections of values. Arrays are ordered collections of values. Sets are unordered collections of unique values. Dictionaries are unordered collections of key-value associations.

Is Swift dictionary ordered?

There is no order. Dictionaries in Swift are an unordered collection type. The order in which the values will be returned cannot be determined. If you need an ordered collection of values, I recommend using an array.

What is a dictionary literal?

A dictionary literal can contain one or more pairs of key/item values. The first expression in a dictionary literal entry is the key value and the second expression is the item value. In a dictionary literal, all key values must be the same type and all item values must the same type.

What is dictionary Swiftui?

A dictionary is a type of hash table, providing fast access to the entries it contains. Each entry in the table is identified using its key, which is a hashable type such as a string or number. You use that key to retrieve the corresponding value, which can be any object.

How do you check if a key is in a dictionary Swift?

Swift – Check if Specific Key is Present in Dictionary

To check if a specific key is present in a Swift dictionary, check if the corresponding value is nil or not. If myDictionary[key] != nil returns true, the key is present in this dictionary, else the key is not there.

How do you create a dictionary array?

Two arrays are required to create a dictionary. One array is used as keys and the other array is used as values. The size of both the arrays should be same, thus making a dictionary with size same as that of the array. Following is the syntax to create a dictionary from two Arrays.

How do I merge dictionaries in Swift?

What is map in Swift?

Swift version: 5.6. The map() method allows us to transform arrays (and indeed any kind of collection) using a transformation closure we specify. The return value will be an array of the same size, containing your transformed elements.

What is difference between dictionary and set?

A set is an unordered collection. A dictionary is an unordered collection of data that stores data in key-value pairs.

Which one is faster array or set in Swift?

Array is faster than set in terms of initialization. Set is slower than an array in terms of initialization because it uses a hash process. The array allows to store duplicate elements in it. Set doesn’t allow to store duplicate elements in it.

What is difference between set and array?

A set is unordered and each element can only appear once in a set. While an array can contain duplicate elements, each value contained in a set is unique.

How do you check if a key is in a dictionary Swift?

Swift – Check if Specific Key is Present in Dictionary

To check if a specific key is present in a Swift dictionary, check if the corresponding value is nil or not. If myDictionary[key] != nil returns true, the key is present in this dictionary, else the key is not there.

What is a protocol in Swift?

In Swift, a protocol defines a blueprint of methods or properties that can then be adopted by classes (or any other types). We use the protocol keyword to define a protocol. For example, protocol Greet { // blueprint of a property var name: String { get } // blueprint of a method func message() }

What is tuple in Swift?

In Swift, a tuple is a group of different values. And, each value inside a tuple can be of different data types. Suppose we need to store information about the name and price of a product, we can create a tuple with a value to store name (string) and another value to store price (float)

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(2020) Swift Tutorial for Beginners: Lesson 17 Dictionaries

(2020) Swift Tutorial for Beginners: Lesson 17 Dictionaries

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Apple Developer Documentation

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Làm việc với Dictionary trong swift

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  Mỗi Value được liên kết với một key duy nhất và bạn có thể tìm kiếm, truy cập value này thôn…
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Swift – Dictionaries

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• Summary of article content: Articles about Swift – Dictionaries Swift 4 dictionaries use unique entifier known as a key to store a value which later can be referenced and looked up through the same key. Unlike items in an … …
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• Table of Contents:

Creating Dictionary

Sequence Based Initialization

Filtering

Dictionary Grouping

Accessing Dictionaries

Modifying Dictionaries

Remove Key-Value Pairs

Iterating Over a Dictionary

Convert to Arrays

The count Property

The empty Property

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Swift Dictionary (With Examples)

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• Summary of article content: Articles about Swift Dictionary (With Examples) Swift dictionary is an unordered collection of items. It stores elements in key/value pairs. Here, keys are unique entifiers that are associated with each … …
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• Table of Contents:

Create a dictionary in Swift

Example Swift Dictionary

Add Elements to a Dictionary

Change Value of Dictionary

Access Elements from Dictionary

Remove an Element from a Dictionary

Other Dictionary Methods

Iterate Over a Dictionary

Find Number of Dictionary Elements

Create an Empty Dictionary

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Swift Dictionary (With Examples)

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• Most searched keywords: Whether you are looking for Swift Dictionary (With Examples) Updating In this tutorial, we’ll learn everything about Swift dictionaries; how they are created, accessing, adding, removing elements from them, and various built-in methods.
• Table of Contents:

Create a dictionary in Swift

Example Swift Dictionary

Add Elements to a Dictionary

Change Value of Dictionary

Access Elements from Dictionary

Remove an Element from a Dictionary

Other Dictionary Methods

Iterate Over a Dictionary

Find Number of Dictionary Elements

Create an Empty Dictionary

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Get Value using Key in Dictionary – Swift

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Swift – Get Value in Dictionary using Key

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Create Dictionary in Swift

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Swift – Create Dictionary

1 Create an empty Dictionary

2 Create a Dictionary with Initial Values

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Collection Types — The Swift Programming Language (Swift 5.7)

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The Swift Programming LanguageSwift 57

Mutability of Collections¶

Arrays¶

Sets¶

Performing Set Operations¶

Dictionaries¶

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Collection Types — The Swift Programming Language (Swift 5.7)

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The Swift Programming LanguageSwift 57

Mutability of Collections¶

Arrays¶

Sets¶

Performing Set Operations¶

Dictionaries¶

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Collection Types — The Swift Programming Language (Swift 5.7)

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The Swift Programming LanguageSwift 57

Mutability of Collections¶

Arrays¶

Sets¶

Performing Set Operations¶

Dictionaries¶

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Dictionaries – a free Hacking with Swift tutorial

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Swift Definition & Meaning | Dictionary.com

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OTHER WORDS FOR swift

Origin of swift

synonym study for swift

OTHER WORDS FROM swift

Words nearby swift

Other definitions for swift (2 of 3)

Other definitions for swift (3 of 3)

Origin of SWIFT

Words related to swift

How to use swift in a sentence

British Dictionary definitions for swift (1 of 2)

Derived forms of swift

Word Origin for swift

British Dictionary definitions for swift (2 of 2)

Derived forms of Swift

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Kiểu từ điển Dictionary trong Swift

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Kiểu từ điển Dictionary

Truy cập Dictionary

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Làm việc với Dictionary trong swift

Dictionary là gì?

Dictionary là một collection để lưu data dưới dạng cặp key – value không theo thứ tự.

Mỗi Value được liên kết với một key duy nhất và bạn có thể tìm kiếm, truy cập value này thông qua key.

Một ví dụ đơn giản, chúng ta cần tìm thủ đô của một quốc gia nào đó trên thế giới.

Thì khi dùng Dictionary (key: quốc gia, value: thủ đô) để lưu trữ chúng ta có thể tìm kiếm được thủ đô một cách nhanh chóng vì chúng đã được lưu theo từng cặp key:value (quốc gia : thủ đô) do đó chỉ cần có tên quốc gia là có ngay thủ đô.

Để clear hơn chúng ta hãy cùng thao tác với Dictionary ngay bây giờ.

Cách khai báo một Dictionary

1. Khai báo với một empty dictionary

Syntax: var someDict = [KeyType : ValueType]() Ví dụ: var someDict = Int : String

2. Khai báo với tập hợp key và value định sẵn

var someDict = [1:”One”, 2:”Two”, 3:”Three”]

3. Khai báo với 2 arrays

var cities = [“Delhi”, “Bangalore”, “Hyderabad”] var distance = [2000, 10, 620] let cityDistanceDic = Dictionary(uniqueKeysWithValues: zip(cities, distance))

Cách truy cập các elements trong Dictionary

1. Truy cập trực tiếp

let someDic = [“a”:1, “b”:2, “c”:3, “d”:4, “e”:5, “f”:6, “g”:7, “h”:8, “i”:9] print(someDic[“a”]) print(someDic[“h”])

2. Dùng vòng lặp để truy cập tất cả các elemements

let someDic = [“a”:1, “b”:2, “c”:3, “d”:4, “e”:5, “f”:6, “g”:7, “h”:8, “i”:9] for (key, value) in someDic { print(“key:\(key) value:\(value)”) }

Cách modify các elememnts trong Dictionary

1. Add thêm element

var someDictionary = [“Nepal”:”Kathmandu”, “China”:”Beijing”, “India”:”NewDelhi”] someDictionary[“Japan”] = “Tokyo” print(someDictionary)

2. Update element

var someDictionary = [“Nepal”:”Kathmandu”, “China”:”Beijing”, >”India”:”NewDelhi”] someDictionary[“Nepal”] = “KATHMANDU” print(someDictionary)

Các function và properties trong Dictionary

1. isEmpty

Property này xác định dictionary có bất kỳ value nào hay không. Nếu không thì return true và ngược lại return false

let someDictionary = [“Nepal”:”Kathmandu”, “China”:”Beijing”, “India”:”NewDelhi”] print(someDictionary.isEmpty) return: false

2. first

Property này dùng để truy cập phần tử đầu tiên của dictionary.

Vì dictionary không có thứ tự, nên .first sẽ không phải là phần tử đầu tiên mà các bạn add vào dictionary đâu nhé. let someDictionary = [“Nepal”:”Kathmandu”, “China”:”Beijing”, “India”:”NewDelhi”] print(someDictionary.first) result: Optional((key: “China”, value: “Beijing”))

Nếu dictionary empty thì sẽ return nil. var someDict = [Int:String]() print(someDict.first) result: nil

3. count

Property này return tổng elements (key:value) có trong dictionary

let someDictionary = [“Nepal”:”Kathmandu”, “China”:”Beijing”, “India”:”NewDelhi”] print(someDictionary.count) return: 3

4. keys

Property này return tất cả keys có trong dictionary

var someDictionary = [“Nepal”:”Kathmandu”, “China”:”Beijing”, “India”:”NewDelhi”] let dictKeys = Array(someDictionary.keys) print(dictKeys) return: [“China”, “India”, “Nepal”]

5. removeValue

Function này sẽ remove element ra khỏi dictionary

var someDictionary = [“Nepal”:”Kathmandu”, “China”:”Beijing”, “India”:”NewDelhi”] someDictionary.removeValue(forKey: “Nepal”) print(someDictionary) return: [“India”: “NewDelhi”, “China”: “Beijing”]

6. filter

Sẽ return các elements sau khi sàng lọc bằng một điều kiện nào đó.

var cities = [“Delhi”,”Bangalore”,”Hyderabad”] var distance = [2000,10,620] let cityDistanceDict = Dictionary(uniqueKeysWithValues: zip(cities, distance)) var closeCities = cityDistanceDict.filter { $0.value < 1000 } print(closeCities) return: ["Hyderabad": 620, "Bangalore": 10] Ví dụ ở đây là in ra những cities có khoảng cách < 1000 Những điều cần lưu ý Khi access vào key không tồn tại trong dictionary thì value = nil var someDictionary = ["Nepal":"Kathmandu", "China":"Beijing", "India":"NewDelhi"] let val = someDictionary["Japan"] print(val) return: nil Keys có sự phân biệt giữa chữ hoa và chữ thường var someDictionary = ["Nepal":"Kathmandu", "China":"Beijing", "India":"NewDelhi"] let lowerCaseVal = someDictionary["nepal"] let uperCaseVal = someDictionary["Nepal"] print(lowerCaseVal) print(uperCaseVal) return: nil Optional("Kathmandu") Default value cho Key không tồn tại var someDictionary = ["Nepal":"Kathmandu", "China":"Beijing", "India":"NewDelhi"] let val = someDictionary["nepal", default:"Not Found"] print(val) return: Not Found Trong trường hợp trên key = "nepal" không tồn tại nên return default value là Not Found. Nếu key = "nepal" tồn tại thì sẽ return value tương ứng của key này var someDictionary = ["Nepal":"Kathmandu", "China":"Beijing", "India":"NewDelhi", "nepal":"aaaaa"] let val = someDictionary["nepal", default:"Not Found"] print(val) return: aaaa Kết: Trên đây là tổng kết sơ lược về Dictionary. Dictionary được dùng rất phổ biến trong lập trình iOS. Hy vọng giúp ích được mọi người.

Swift – Dictionaries

Swift – Dictionaries

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Swift 4 dictionaries are used to store unordered lists of values of the same type. Swift 4 puts strict checking which does not allow you to enter a wrong type in a dictionary even by mistake.

Swift 4 dictionaries use unique identifier known as a key to store a value which later can be referenced and looked up through the same key. Unlike items in an array, items in a dictionary do not have a specified order. You can use a dictionary when you need to look up values based on their identifiers.

A dictionary key can be either an integer or a string without a restriction, but it should be unique within a dictionary.

If you assign a created dictionary to a variable, then it is always mutable which means you can change it by adding, removing, or changing its items. But if you assign a dictionary to a constant, then that dictionary is immutable, and its size and contents cannot be changed.

Creating Dictionary

You can create an empty dictionary of a certain type using the following initializer syntax −

var someDict = [KeyType: ValueType]()

You can use the following simple syntax to create an empty dictionary whose key will be of Int type and the associated values will be strings −

var someDict = [Int: String]()

Here is an example to create a dictionary from a set of given values −

var someDict:[Int:String] = [1:”One”, 2:”Two”, 3:”Three”]

Sequence Based Initialization

Swift 4 allows you to create Dictionary from arrays (Key-Value Pairs.)

var cities = [“Delhi”,”Bangalore”,”Hyderabad”]

You can use the following simple syntax to create an empty dictionary whose key will be of Int type and the associated values will be strings −

var Distance = [2000,10, 620]

Here is an example to create a dictionary from a set of given values −

let cityDistanceDict = Dictionary(uniqueKeysWithValues: zip(cities, Distance))

The above lines of code will create a dictionary with Cities as key and Distance as Value −

Filtering

Swift 4 allows you to filter values from a dictionary.

var closeCities = cityDistanceDict.filter { $0.value < 1000 } If we run the above code our closeCities Dictionary will be. ["Bangalore" : 10 , "Hyderabad" : 620] Dictionary Grouping Swift 4 allows you to create grouping of Dictionary values. var cities = ["Delhi","Bangalore","Hyderabad","Dehradun","Bihar"] You can use the following simple syntax to group the values of dictionary according to first alphabet. var GroupedCities = Dictionary(grouping: cities ) { $0.first! } The result of above code will be ["D" :["Delhi","Dehradun"], "B" : ["Bengaluru","Bihar"], "H" : ["Hyderabad"]] Accessing Dictionaries You can retrieve a value from a dictionary by using subscript syntax, passing the key of the value you want to retrieve within square brackets immediately after the name of the dictionary as follows − var someVar = someDict[key] Let's check the following example to create, initialize, and access values from a dictionary − var someDict:[Int:String] = [1:"One", 2:"Two", 3:"Three"] var someVar = someDict[1] print( "Value of key = 1 is \(someVar)" ) print( "Value of key = 2 is \(someDict[2])" ) print( "Value of key = 3 is \(someDict[3])" ) When the above code is compiled and executed, it produces the following result − Value of key = 1 is Optional("One") Value of key = 2 is Optional("Two") Value of key = 3 is Optional("Three") Modifying Dictionaries You can use updateValue(forKey:) method to add an existing value to a given key of the dictionary. This method returns an optional value of the dictionary's value type. Here is a simple example − var someDict:[Int:String] = [1:"One", 2:"Two", 3:"Three"] var oldVal = someDict.updateValue("New value of one", forKey: 1) var someVar = someDict[1] print( "Old value of key = 1 is \(oldVal)" ) print( "Value of key = 1 is \(someVar)" ) print( "Value of key = 2 is \(someDict[2])" ) print( "Value of key = 3 is \(someDict[3])" ) When the above code is compiled and executed, it produces the following result − Old value of key = 1 is Optional("One") Value of key = 1 is Optional("New value of one") Value of key = 2 is Optional("Two") Value of key = 3 is Optional("Three") You can modify an existing element of a dictionary by assigning new value at a given key as shown in the following example − var someDict:[Int:String] = [1:"One", 2:"Two", 3:"Three"] var oldVal = someDict[1] someDict[1] = "New value of one" var someVar = someDict[1] print( "Old value of key = 1 is \(oldVal)" ) print( "Value of key = 1 is \(someVar)" ) print( "Value of key = 2 is \(someDict[2])" ) print( "Value of key = 3 is \(someDict[3])" ) When the above code is compiled and executed, it produces the following result − Old value of key = 1 is Optional("One") Value of key = 1 is Optional("New value of one") Value of key = 2 is Optional("Two") Value of key = 3 is Optional("Three") Remove Key-Value Pairs You can use removeValueForKey() method to remove a key-value pair from a dictionary. This method removes the key-value pair if it exists and returns the removed value, or returns nil if no value existed. Here is a simple example − var someDict:[Int:String] = [1:"One", 2:"Two", 3:"Three"] var removedValue = someDict.removeValue(forKey: 2) print( "Value of key = 1 is \(someDict[1])" ) print( "Value of key = 2 is \(someDict[2])" ) print( "Value of key = 3 is \(someDict[3])" ) When the above code is compiled and executed, it produces the following result − Value of key = 1 is Optional("One") Value of key = 2 is nil Value of key = 3 is Optional("Three") You can also use subscript syntax to remove a key-value pair from a dictionary by assigning a value of nil for that key. Here is a simple example − var someDict:[Int:String] = [1:"One", 2:"Two", 3:"Three"] someDict[2] = nil print( "Value of key = 1 is \(someDict[1])" ) print( "Value of key = 2 is \(someDict[2])" ) print( "Value of key = 3 is \(someDict[3])" ) When the above code is compiled and executed, it produces the following result − Value of key = 1 is Optional("One") Value of key = 2 is nil Value of key = 3 is Optional("Three") Iterating Over a Dictionary You can use a for-in loop to iterate over the entire set of key-value pairs in a Dictionary as shown in the following example − var someDict:[Int:String] = [1:"One", 2:"Two", 3:"Three"] for (index, keyValue) in someDict.enumerated() { print("Dictionary key \(index) - Dictionary value \(keyValue)") } When the above code is compiled and executed, it produces the following result − Dictionary key 2 - Dictionary value Two Dictionary key 3 - Dictionary value Three Dictionary key 1 - Dictionary value One You can use enumerate() function which returns the index of the item along with its (key, value) pair as shown below in the example − var someDict:[Int:String] = [1:"One", 2:"Two", 3:"Three"] for (key, value) in someDict.enumerated() { print("Dictionary key \(key) - Dictionary value \(value)") } When the above code is compiled and executed, it produces the following result − Dictionary key 0 - Dictionary value (key: 2, value: "Two") Dictionary key 1 - Dictionary value (key: 3, value: "Three") Dictionary key 2 - Dictionary value (key: 1, value: "One") Convert to Arrays You can extract a list of key-value pairs from a given dictionary to build separate arrays for both keys and values. Here is an example − var someDict:[Int:String] = [1:"One", 2:"Two", 3:"Three"] let dictKeys = [Int](someDict.keys) let dictValues = [String](someDict.values) print("Print Dictionary Keys") for (key) in dictKeys { print("\(key)") } print("Print Dictionary Values") for (value) in dictValues { print("\(value)") } When the above code is compiled and executed, it produces the following result − Print Dictionary Keys 2 3 1 Print Dictionary Values Two Three One The count Property You can use the read-only count property of a dictionary to find out the number of items in a dictionary as shown below − var someDict1:[Int:String] = [1:"One", 2:"Two", 3:"Three"] var someDict2:[Int:String] = [4:"Four", 5:"Five"] print("Total items in someDict1 = \(someDict1.count)") print("Total items in someDict2 = \(someDict2.count)") When the above code is compiled and executed, it produces the following result − Total items in someDict1 = 3 Total items in someDict2 = 2 The empty Property You can use read-only empty property of a dictionary to find out whether a dictionary is empty or not, as shown below − var someDict1:[Int:String] = [1:"One", 2:"Two", 3:"Three"] var someDict2:[Int:String] = [4:"Four", 5:"Five"] var someDict3:[Int:String] = [Int:String]() print("someDict1 = \(someDict1.isEmpty)") print("someDict2 = \(someDict2.isEmpty)") print("someDict3 = \(someDict3.isEmpty)") When the above code is compiled and executed, it produces the following result − someDict1 = false someDict2 = false someDict3 = true

Swift Dictionary (With Examples)

Swift dictionary is an unordered collection of items. It stores elements in key/value pairs. Here, keys are unique identifiers that are associated with each value.

Let’s see an example.

If we want to store information about countries and their capitals, we can create a dictionary with country names as keys and capitals as values.

Keys Values Nepal Kathmandu Italy Rome England London

Create a dictionary in Swift

Here’s how we can create a dictionary in Swift.

var capitalCity = [“Nepal”: “Kathmandu”, “Italy”: “Rome”, “England”: “London”] print(capitalCity)

Output

[“Nepal”: “Kathmandu”, “England”: “London”, “Italy”: “Rome”]

In the above example, we have created a dictionary named capitalCity . Here,

Keys are “Nepal” , “Italy” , “England”

are , , Values are “Kathmandu” , “Rome” , “London”

When we run this code, we might get output in a different order. This is because the dictionary has no particular order.

Note: Here, keys and values both are of String type. We can also have keys and values of different data types.

Example: Swift Dictionary

// dictionary with keys and values of different data types var numbers = [1: “One”, 2: “Two”, 3: “Three”] print(numbers)

Output

[3: “Three”, 1: “One”, 2: “Two”]

In the above example, we have created a dictionary named numbers . Here, keys are of Int type and values are of String type.

Add Elements to a Dictionary

We can add elements to a dictionary using the name of the dictionary with [] . For example,

var capitalCity = [“Nepal”: “Kathmandu”, “England”: “London”] print(“Initial Dictionary: “,capitalCity) capitalCity[“Japan”] = “Tokyo” print(“Updated Dictionary: “,capitalCity) print(capitalCity[“Japan”])

Output

Initial Dictionary: [“Nepal”: “Kathmandu”, “England”: “London”] Updated Dictionary: [“Nepal”: “Kathmandu”, “England”: “London”, “Japan”: “Tokyo”]

In the above example, we have created a dictionary named capitalCity . Notice the line,

capitalCity[“Japan”] = “Tokyo”

Here, we have added a new element to capitalCity with key: Japan and value: Tokyo .

Change Value of Dictionary

We can also use [] to change the value associated with a particular key. For example,

var studentID = [111: “Eric”, 112: “Kyle”, 113: “Butters”] print(“Initial Dictionary: “, studentID) studentID[112] = “Stan” print(“Updated Dictionary: “, studentID)

Output

Initial Dictionary: [111: “Eric”, 113: “Butters”, 112: “Kyle”] Updated Dictionary: [111: “Eric”, 113: “Butters”, 112: “Stan”]

In the above example, we have created a dictionary named studentID . Initially, the value associated with the key 112 is “Kyle” . Now, notice the line,

studentID[112] = “Stan”

Here, we have changed the value associated with the key 112 to “Stan” .

Access Elements from Dictionary

In Swift, we can access the keys and values of a dictionary independently.

1. Access Keys Only

We use the keys property to access all the keys from the dictionary. For Example,

var cities = [“Nepal”:”Kathmandu”, “China”:”Beijing”, “Japan”:”Tokyo”] print(“Dictionary: “, cities) // cities.keys return all keys of cities var countryName = Array(cities.keys) print(“Keys: “, countryName)

Output

Dictionary: [“Nepal”: “Kathmandu”, “Japan”: “Tokyo”, “China”: “Beijing”] Keys: [“Nepal”, “Japan”, “China”]

2. Access Values Only

Similarly, we use the values property to access all the values from the dictionary. For Example,

var cities = [“Nepal”:”Kathmandu”, “China”:”Beijing”, “Japan”:”Tokyo”] print(“Dictionary: “, cities) // cities.values return all values of cities var countryName = Array(cities.values) print(“Values: “, countryName)

Output

Dictionary: [“Nepal”: “Kathmandu”, “China”: “Beijing”, “Japan”: “Tokyo”] Values: [“Kathmandu”, “Beijing”, “Tokyo”]

Remove an Element from a Dictionary

We use the removeValue() method to remove an element from the dictionary. For example,

var studentID = [111: “Eric”, 112: “Kyle”, 113: “Butters”] print(“Initial Dictionary: “, studentID) var removedValue = studentID.removeValue(forKey: 112) print(“Dictionary After removeValue(): “, studentID)

Output

Initial Dictionary: [113: “Butters”, 111: “Eric”, 112: “Kyle”] Dictionary After removeValue(): [111: “Eric”, 113: “Butters”]

Here, we have created a dictionary named studentID . Notice the

var removedValue = studentID.removeValue(forKey: 112)

The removeValue() method removes the element associated with the key 112 .

Note: We can also use removeAll() function to remove all elements of a dictionary.

Other Dictionary Methods

Method Description sorted() sorts dictionary elements shuffled() changes the order of dictionary elements contains() checks if the specified element is present randomElement() returns a random element from the dictionary firstIndex() returns the index of the specified element

Iterate Over a Dictionary

We use the for loop to iterate over the elements of a dictionary. For example,

var classification = [“Fruit”: “Apple”, “Vegetable”: “Broccoli”, “Beverage”: “Milk”] print(“Keys: Values”) for (key,value) in classification { print(“\(key): \(value)”) }

Output

Keys: Values Vegetable: Broccoli Beverage: Milk Fruit: Apple

Find Number of Dictionary Elements

We can use the count property to find the number of elements present in a dictionary. For example,

var studentID = [111: “Eric”, 112: “Kyle”, 113: “Butters”] print(studentID.count)

Output

3

Create an Empty Dictionary

In Swift, we can also create an empty dictionary. For example,

var emptyDictionary = [Int: String]() print(“Empty Dictionary: “,emptyDictionary)

Output

Empty Dictionary: [:]

In the above example, we have created an empty dictionary. Notice the expression

[Int: String]()

Here,

Int specifies that keys of the dictionary will be of integer type

specifies that keys of the dictionary will be of integer type String specifies that values of the dictionary will be of String type.

Note: It is compulsory to specify the data type of dictionary while creating an empty dictionary.

So you have finished reading the swift dictionary topic article, if you find this article useful, please share it. Thank you very much. See more: Get key from dictionary swift, Append dictionary Swift, Nested dictionary swift, Get value dictionary swift, Dictionary Swift example, Dictionary to string swift, Array Swift, Check key exist in dictionary Swift