Swift – Print Dictionary Keys
Welcome to Swift Tutorial. In this tutorial, we will learn how to print all the keys present in a dictionary.
To print all the keys of a dictionary, we can iterate over the keys returned by Dictionary.keys or iterate through each (key, value) pair of the dictionary and then access the key alone.
Example 1 – Get all keys in a Swift Dictionary
In this example, we will create a Swift Dictionary with some initial values and print all the keys of the Dictionary.
main.swift
var myDictionary:[String:Int] = ["Mohan":75, "Raghu":82, "John":79]
for key in myDictionary.keys {
print("\(key)")
}
Output
Raghu
John
Mohan
In this example, myDictionary.keys returns an array with all the keys in it. And we used a for loop to iterate over the keys String array.
Example 2 – Print all keys in a Swift Dictionary using for loop
In this example, we will create a Swift Dictionary with some initial values and print all the keys of the Dictionary.
main.swift
var myDictionary:[String:Int] = ["Mohan":75, "Raghu":82, "John":79]
for (key, value) in myDictionary {
print("\(key)")
}
Output
Raghu
John
Mohan
In this example, we used a for loop to iterate over the (key, value) pairs of the Dictionary.
You might get a warning that value
has not been used inside the loop. You can suppress this warning by using an underscore _
in the place of value
.
Example 3 – Print all keys in a Swift Dictionary along with an index/offset
In this example, we will create a Swift Dictionary with some initial values and print all the keys of the enumerated Dictionary.
main.swift
var myDictionary:[String:Int] = ["Mohan":75, "Raghu":82, "John":79]
for (item) in myDictionary.enumerated() {
print("\(item.offset): \(item.element.key)")
}
Output
0: Mohan
1: John
2: Raghu
Each item in the enumerated dictionary has the structure of
(offset: 0, element: (key: "Mohan", value: 75))
So, when you iterate over an enumerated dictionary, you will get offset and the element for each iteration. Which is why we used item.element
.
As we need to get the key only, we have specifically used item.element.key
.
Conclusion
In this Swift Tutorial, we learned how to print keys of a Dictionary using Dictionary.keys.