Add Elements to a Dictionary
We can add elements to a dictionary by prefixing the dictionary name with []. As an example,
var myDict:[String:Int] = ["sapna":75, "saurabh":82, "miller":79]
myDict["boult"] = 88
for (key, value) in myDict {
print("\(key) : \(value)")
}
Output:
saurabh : 82
sapna : 75
miller : 79
boult : 88
Here, we have added a new element to cap_City with key: Jharkhand and value: Ranchi.
Change Value of Dictionary
We may also use [] to modify the value associated with a certain key. As an example,
var stu_ID = [101: "Saurabh", 102: "Gaurav", 103: "Anand"]
print("Initial Dictionary: ", stu_ID)
stu_ID[102] = "RamCharan"
print("Updated Dictionary: ", stu_ID)
Output:
Initial Dictionary: [101: "Saurabh", 102: "Gaurav", 103: "Anand"]
Updated Dictionary: [101: "Saurabh", 102: "RamCharan", 103: "Anand"]
Access Elements from Dictionary
We can access the keys and values of a dictionary separately in Swift.
To access all of the keys in the dictionary, we use the keys property. As an example,
var cities = ["Bihar": "Patna", "Uttar Pradesh": "Lucknow", "Jharkhand": "Ranchi"]
print("Dictionary: ", cities)
var country_Name = Array(cities.keys)
print("Keys: ", country_Name)
Output:
Dictionary: ["Bihar": "Patna", "Uttar Pradesh": "Lucknow", "Jharkhand": "Ranchi"]
Keys: ["Bihar", "Uttar Pradesh", "Jharkhand"]
Remove an Element from a Dictionary
To delete an element from the dictionary, we utilize the removeValue() method. As an example,
var stu_ID = [101: "Saurabh", 102: "RamCharan", 103: "Anand"]
print("Initial Dictionary: ", stu_ID)
var removedValue = stu_ID.removeValue(forKey: 102)
print("Dictionary After removeValue(): ", stu_ID)
Output:
Initial Dictionary: [101: "Saurabh", 102: "RamCharan", 103: "Anand"]
Dictionary After removeValue(): [101: "Saurabh", 103: "Anand"]
Iterate Over a Dictionary
The for loop is used to go over the elements of a dictionary. As an example,
var Names = [101: "Saurabh", 102: "RamCharan", 103: "Anand"]
print("Keys: Values")
for (key,value) in Names {
print("\(key): \(value)")
}
Output:
Keys: Values
101: Saurabh
102: RamCharan
103: Anand
Find Number of Dictionary Elements
The count property can be used to determine the number of elements in a dictionary. As an example,
var stu_ID = [101: "Saurabh", 102: "RamCharan", 103: "Anand"]
print(stu_ID.count)
Output:
3
Create an Empty Dictionary
We can also generate an empty dictionary in Swift. As an example,
var emptyDict = [Int: String]()
print("Empty Dictionary: ",emptyDict)
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
String specifies that values of the dictionary will be of String type.
Note: When constructing an empty dictionary, you must define the data type of the dictionary.
Frequently Asked Questions
What are the online websites for swift programming?
Some of the available sites for online coding in swift language are Swiftstub.com, Runswiftlang.com, iswift.org, etc.
What are the most important features of swift?
Swift has the following significant features: More impressive structs and enums, Protocol oriented, Optional Types, etc.
What is init() in Swift?
The process of preparing an instance of an enumeration, structure, or class for use is known as initialization.
What are the control transfer statements that are used in iOS swift?
The following control transfer statements are used in iOS Swift:
Return, Break, Continue, and Fallthrough.
Conclusion
In this article, we have extensively discussed the concept of the Swift dictionary. We started with the introduction of Swift dictionary, creating Swift dictionary, adding elements in Swift dictionary, changing values in Swift dictionary, accessing elements in Swift dictionary, removing elements in Swift dictionary, and concluded with iterating over Swift dictionary.
After reading about the swift dictionary, are you not feeling excited to read/explore more articles on the topic of file systems? Don't worry; Coding Ninjas has you covered. To learn, see Swift Syntax and Program, Swift continue and fallthrough statements, and Kotlin Architecture and Environment Setup.
Also check out - Data Dictionary In Software Engineering
Refer to our Guided Path on Coding Ninjas Studio to upskill yourself in Data Structures and Algorithms, Competitive Programming, JavaScript, System Design, and many more! If you want to test your capacity in coding, you may check out the mock test series and participate in the contests hosted on Coding Ninjas Studio website. But if you have just started learning and are looking for questions asked by tech giants like Amazon, Microsoft, google, Uber, etc; you must look at the problems, interview experiences, and interview bundle for placement preparations.
you may also consider our paid courses to give your career an edge over others!
Do upvote our blogs if you find them helpful and engaging!
Happy Learning!
8+ registered 